ABC

Definition

Expansile pseudotumor of reactive hemorrhagic tissue arising in bone

- characterised by blood filled spaces separated by fibrous tissue

Types

Primary 50%

- arise de novo 

Secondary 50%

- in association with other tumours 

- probably secondary to haemorrhage into 1° tumour

- GCT / chondroblastoma / osteoblastoma / osteosarcoma

- often only small component

- should treat as underlying 1° tumour

Site

Metaphysis of long bones

- proximal humerus

- femur

- tibia

Posterior elements of vertebra

Epidemiology

Teenagers

- 80% occur in 10-20 year range

F>M

NHx

Pathological fracture rare

May resolve with fracture or skeletal maturity

X-ray

Multi-loculated lesion

- eccentric

- expansile

- cortical thinning

Bone Scan

Usually increased uptake

- centre may have decreased uptake

Exclude polyostotic disease

MRI 

Haemosiderin content

- low to intermediate signal on T1 and T2

Fluid - Fluid levels 

- due to sedimentation of RBC's & serum within the cavities

- patient must remain motionless for 10 minutes prior to the scan being performed

- allows time for sedimentation

DDx

Fibrous dysplasia

GCT

ABC

Infection

Unicameral Bone Cyst

Osteosarcoma

Pathology

Gross

Blood filled spaces with fibrous septa

Histology

Cells

- haemosiderin-laden macrophages

- multinucleated giant cells

Septa

- fibrous stroma

- small amounts of osteoid

Management

Non operative

Can observe majority

- need to avoid contact sports

Operative

Indications

Biopsy / diagnose

Potential instability - proximal femur / spine

Pain

Recurrent fracture / debilitating

Options

Currettage and bone graft

Allograft / Joint Replacement

Embolisation

Sclerotherapy

Currettage and bone grafting

Concept

Principles of biopsy approach

- confirm diagnosis on frozen section

- proceed to treatment

Indication

Must be able to preserve articular surface

Technique

Full and careful curettage

- intra-lesional treatment

- need to burr away all of lesion

- must take care as bone very thin

- areas of fracture not uncommon

- must beware growth plates in skeletally immature

- supplement with bone graft / bone marrow aspirate / PMMA

Resection and Allograft / TJR

Indications

Articular cartilage not salvageable

Selective Arterial Embolisation

Indications

- preoperative in spine lesions

Results

Rossi et al Skeletal Radiol 2010

- 55 cases both spine and appedicular with N butyl cryanoacrylate

- successful in 94% cases

- a second (25%) and third (14%) embolisation required

- 2 cases of skin necrosis and one transient paresis

Sclerotherapy

Results

Rastogi et al JBJS Br 2006

- percutaneous sclerotherapy with polidocanol in 72 patients under II guidance

- all had histological diagnosis prior to treatment

- 84.5% clinical response

- required between 1 and 5 treatments (average 3)

- 2 recurrences successfully treated with repeat sclerotherapy

Varshney et al Clin Orthop Relat Research 2010

- RCT of sclerotherapy v intralesional resection of 94 ABCs

- 3 year follow up

- 93% healing in sclerotherapy group with minimal complications

- 84% healing in operative group with 3 deep and 5 superficial infections and 2 growth disturbances

Spine

Papagelopoulos et al Spine 1998

- 52 cases in the spine

- treated with extralesional and intralesional excision with bone grafting

- 10% recurrence at 10 years, all presenting within 6 months post surgery

- 4 patients had postoperative radiotherapy

- 1 died of radiation related osteosarcoma, 1 of intraoperative bleeding

- now recommend preoperative embolisation

Adamantinoma

Definition

Rare low-grade malignant tumour

- cell of origin unknown

Epidemiology

Usually second or third decade of life

Site

90% diaphysis of tibia 

Mandible

X-ray

Most common anterior cortex of tibia

Soap-bubble appearance

Eccentrically located

- well circumscribed

- slightly expansile

- cortical thickening

- little or no periosteal reaction

- can have late deformity

DDx

Fibrous dyplasia

Osteofibrous dysplasia / Ossifying fibroma / Osteosarcoma

Giant cell tumour

ABC

Chondrosarcoma / CS

Infection / osteomyelitis

Unicameral bone cyst

Diaphyseal lesion / HALFEE

- Histiocytoma

- Adamantinoma

- leukemia

- FD

- EG

- Ewings

Pathology

Two distinctly different components

1.  Epithelial origin 

- composed of squamous cells and epithelial pearls 

2.  Mesenchymal origin 

- composed of immature mesenchymal cells and spicules of dysplastic bone

- closely resembles the pattern of fibrous dysplasia and its variant ossifying fibroma 

Adamantinoma is considered by some to be a malignant variant of fibrous dysplasia

- resemblance of the mesenchymal component to fibrous dysplasia / ossifying fibroma

- the presence of the epithelial component makes adamantinoma a distinctly different entity

NHx

Intra-osseous, intra-cortical Stage 1A Osteosarcoma

Metastasis in 20% of cases

Management

Wide excision

Biopsy followed by wide resection

- chemo and radiotherapy ineffective

- need to address bone loss

- vascularised fibular graft / allograft / bone transport

Results

Qureshi et al JBJS Am 2000

- multicentred retrospective review of 70 cases

- average age 31, more common in males

- limb salvage attempted in 91% and successful in 84%

- up to 50% complication rate with limb reconstruction (fracture, non union)

- wide operative margins associated with lower recurrence rates

- 87% 10 year survival

Benign Fibrous Histiocytoma

Epidemiology

Older patients

- eipiphysis / diaphysis of long bones usually

Xray

Lytic lesion with sclerotic rim

Histology

Benign

- foam cells

- lipid filled cells

Treatment

Curette and bone graft

- chance of recurrence

Chondroblastoma

Definition

Rare cartilage tumour 

Epidemiology

1% of bone tumours / rare

- typically in adolescents

NHx

Usually benign

- but aggressive / frankly malignant behaviour reported

- locally aggressive

- can have pulmonary metastasis

Location

Arises in secondary ossification centre / epiphysis

- proximal tibia / knee

- proximal femur / hip

Develops < physis closes (unlike GCT)

Clinical

Usually painful

- may produce limitation of joint ROM

May produce altered epiphyseal growth in young children

X-ray

Eccentric epiphyseal 

- well-defined lucency

- thin sclerotic reactive rim

Often internal stippled calcification

- popcorn or chicken wire calcification in 25%

- ± metaphyseal periosteal reaction

MRI

Rarely diagnostic

- many tumours will have areas of hemorrhage

- causes high signal intensity on T2

- i.e. GCT / ABC / chondroblastoma

Pathology

Histology

Stage 2 lesion typically / benign active

- active / intracapsular but with aggressive stroma

Sheets of chondroblasts and amorphous cartilage

- polygonal cells

- bluish cytoplasm

- cobblestone appearance of fine surrounding calcium like "chicken wire"

- occasional giant cells 

Atypical cartilage matrix

- stain +ve for S100 

- chondroid Matrix

DDx

Epiphyseal lesion in adults

- chondroblastoma

- GCT

- clear cell chondrosarcoma

- infection

- telangiectatic osteosarcoma

Management

Principles

- difficult to eradicate due to anatomic position without damaging joint or physis

- i.e. located in hip and knee close to joint surface

Options

1.  Currettage and bone graft

2.  Radiofrequency ablation

3.  Wide excision / usually necessitate allograft reconstruction or joint replacement

Intra - Lesional Curettage + Bone Graft

Technique

- intra-articular exposure required

- meticulous debridement with burr

- local adjuvant treatment - Phenol / Liquid N2

- avoid damage to physis 

- allograft / autograft / PMMA

Problem

- may not be possible to prevent injury to joint due to location

Recurrence

More common in femur and foot/ankle

- should have CT chest to exclude pulmonary metastasis

- can be cured by second currettage

Results

Sallhan et al JBJS Am 2009

- retrospective review of 87 cases

- 32% recurrence by 24 months

- most likely with epiphyseal lesions

Ramappa et al JBJS Am 2000

- 73 patients treateed with 15% local recurrence

- 1 patient recurred 3 times

- one patient died of metastasis

- one patient was cured of metastasis by aggressive surgery

Radiofrequency ablation

Results

Rybak et al Radiology 2009

- 14 patients treated and available for follow up

- 12 had good relief of symptoms with no further treatment required

- 1 patient required repeat treatment

- 1 patient had collapse of chondral surface with residual tumour

Wide Resection

Indication

- usually requires resection / reconstruction of joint

- indicated for second recurrence

Pulmonary metastasis

- resect if possible

Chondromyxoid Fibroma

Definition

Benign neoplasm of cartilaginous origin composed primarily of myxoid cartilage

Previously thought to be Chondrosarcoma

Epidemiology

Very rare tumour

- young adults 10-30

- M:F 2:1

Location

Common upper tibia

- metaphysis of long bones

- lower limb predilection

Clinical

Tenderness

Local bulge

X-ray

Eccentrically placed metaphysis

- round or oval lucency

- well-defined sclerotic margin

- local expansion but cortex intact

- erodes / balloons the cortex

- characteristic buttress of periosteal new bone formation

Indistinguishable from an ABC

Pathology

Lobulated areas of spindle shaped stellate cells

- abundant myxoid / chondroid intercellular material

- multinucleated giant Cells

- merging of benign elements - hyaline cartilage / myxoid tissue / fibrous tissue

DDx

ABC 

Fibrous cortical defect

Fibrous Dysplasia

Management

Intra-lesional curettage & bone grafting

- recurrence common (40%)

- treat with wide resection

If Stage 3 lesion consider marginal or wide resection

Eosinophilic Granuloma

Definition

Langerhan's Cell Histiocytosis

- non-neoplastic disorder

- characterised by infiltration by histiocytic cells (Monocyte / macrophage lineage)

Group of granulomatous inflammatory processes of unknown aetiology

- involve the reticuloendothelial component of the bone marrow, parenchymal organs, and skin

Types 

E - H - L

- 5-20 years

- only manifestation is Osseous

- one or more lesions

2.  Hand-Schuller-Christian Disease (20%)

Think of as multiple EG's 

- more widespread granulomas

- systemic manifestation of EG 

Classically triad of

- diabetes insipidus  (parapituitary involvement)

- exopthalmos (orbital involvement)

- skull defects

Plus

- osseous lesions with mild to moderate visceral involvement

- lymphadenopathy

- hepatosplenomegaly both from EG

- skin lesions

- pulmonary disease

Less aggressive than LS

- 10% die

3.  Letterer-Siwe Disease (10%) 

- often infants < 1

- probably unrelated neoplastic condition

- rare disseminated disease of infants with fulminant course

- major visceral involvement: RES, pulmonary, anaemia

- death from hepatic failure

- less osseous involvement

Aetiology 

Unknown

Cell of origin is Langerhan's Cell

- ? immunoregulation disorder

- deficiency of Suppressor T-Cells

- uncontrolled macrophage proliferation 

Clinical 

Eosinophilic Granuloma (70%) 

- affects children age 4-7 years

- presentation variable & non specific

Back pain from vertebral lesion (most common presentation) 

Localised swelling (especially Skull)

Pain, limp & muscle wasting with pelvic or leg EG

- pathological fracture

Location 

Any bone may be affected

- skull / spine / femur / flat bones (ribs, pelvis)

Less common in long bones

- diaphyseal

- solitary lesion in 50%

- if multiple, < 3 lesions

Laboratory

Inconsistent & moderate elevation of ESR + anaemia

X-ray

1.  Vertebra Plana 

- compression of body

- vertebral body widened

- usually involves end plate rather than neural arch

- discs intact

DDx

- Ewings

- MM, Mets, Lymphoma, Leukaemia

- ABC

- infection

2.  Long Bones 

Diaphyseal osteolytic lesion

- thin sclerotic rim with endosteal scalloping

- cortical expansion with overlying periosteal reaction

- appearances vary according to stage of healing

DDx

- HALFEE

3.  Skull 

- most common site

- multiple punched out lucencies

- coalesce to give geographic skull

- typically bevelled edge appearance to lesion

MRI 

Lesion is low signal on T1 & high signal on T2 

- enhancing brightly with gadolinium (good discriminator)

DDx

Need to rule out HSCD or LS

- bone scan & skeletal survey

Pathology

Defect filled with lipid-laden histiocytes with eosinophilic cytoplasm

- plasma cells (blue with cartwheel nucleus)

- eosinophils (pink with bilobed nucleus)

- plasma cells with occasional eosinophils

Cytoplasm of cells contains specific Inclusion X bodies 

- same as Birbeck granules in Langerhans Cell 

- visible under EM

Positive staining for S100

NHx

Usually self-limiting

- fibroblasts obliterate histiocytes & inflammatory response

- tissue replaced by bone

Management

Vertebroplanar in infant

- self limiting

- will resolve

- no treatment required

Surgical indications

- symptomatic

- progressive

- neurological deficit

- at risk of pathological fracture

Options

1.  Intralesional steroid

Rimondi et al Skeletal Radiol 2009

- CT guided percutaneous intralesional methylprednisone

- success in 17/19 patients

- remaining two found to have systemic disease

Yasko et al JBJS Am

- 35 lesions

- resolution in all but one

- 97% success

2.  Curettage and bone grafting

HCSD & LSD

Systemic treament / chemotherapy

- radiotherapy for localised lesions

- alkylating agents + steroids

- poor results if recurrence within 1 year

Fibrous Cortical Defect

AKA

Non Ossifying Fibroma

Definition

A hamartomatous defect in the metaphyseal cortex of skeletally-immature adolescents

Fibrous cortical defect 

- < 2cm in diameter

Non ossifying fibromas 

- > 2cm

Aetiology

Localised defect in cortex of long bone

- failure of bone to form

Epidemiology

Most common skeletal lesion

- 35% of young children

- most common cause of pathological fracture in children

NHx

Self limiting

- usually ossify by early adulthood

- ? become bone islands

Location

Distal femur

Distal tibia

Clinical

Child

- incidental finding

- pathological fracture

X-ray

Non-Ossifying Fibroma 

- > 2 cm

- eccentric metaphyseal lesion

- sclerotic margin

- slight expansion of cortex

- usually < 1/3 diameter of bone

Fibrous Cortical Defect

- < 2cm

- small cortical lucency 

- sharply defined border

Pathology

Fibroblasts in whorling fibrous stroma

- multinucleated giant cells

- no bone formation

Management

Biopsy

Usually don't require biopsy

- biopsy if uncertain

Fibrous Cortical Defect

Management

Serial observation

- xray yearly

- 35% of children have them

Non Ossifying Fibroma

Indication for surgery

- large lesions

- > 1/2 diameter of bone

Management

- curettage & bone graft

Pathological fracture

Management

1.  Treat closed if possible

- fracture heals in normal length of time

- lesion may heal with fracture union

2.  If persists, curettage / graft

Fibrous Dysplasia

Definition

Developmental hamartoma in which areas of the skeleton fail to mature normally

- remain indefinitely as immature, poorly mineralized trabeculae

Pathology

Hamartoma of bone and fibrous tissue

McCune - Albright's Syndrome

Rare triad of

1.  Fibrous Dysplasia

2.  Cafe-au-Lait Spots

- irregular 'Coast of Maine'

- compare with regular outline of 'Coast of California' in NF

3.  Precocious puberty

Malignant transformation

Monostotic 0.4%

Polyostotic / Albright's 4%

- OS / FS / CS

Inheritance

Usually non genetic inheritance

Osteofibrous Dysplasia

Only Tibia

- precursor Adamantinoma

- more dense with trabecular pattern

- plump rimming osteoblasts

Types

1. Monostotic 85%

2. Polyostotic 15%

3. Associated with endocrinopathy

- Vit D Resistant Rickets

- Hyperthyroidism

- DM

- Acromegaly

- Cushing' s syndrome

Location

Any bone

Femur

- involved in 90% polyostotic

Tibia

Skull / maxilla / ribs

NHx

Usually diagnosed in children and adolescents

Remains relatively unchanged throughout life

- in keeping with developmental abnormality 

Clinical

Monostotic

- incidental finding

Polyostotic

- usually present in childhood

- pain (indicates microfracture)

- pathological fracture

- limp

- deformity

X-ray

Intramedullary diaphyseal lesion

- 'ground glass appearance'

- tissue that is more lucent with a similar to the density of cancellous bone

- homogeneous with no visible trabecular pattern

Thinned, slightly bulged cortex

- ± endosteal scalloping

± Angular deformity at site of lesion

Coxa vara of proximal femur

- Shepherd's Crook deformity

- secondary LLD

Sabre tibia

CT

Bone Scan

Skeletal Survey

- mono v polyostotic

- look for other lesions

MRI

Low T1 SI

Low - High T2 SI

Pathology

"Chinese letters"

- strands of osteoid & bone arising from fibrous stroma

- irregularly shaped bony trabeculae in fibrous stroma

Management

Principles

Basic rule is don't operate unless deformity

Any morcellised bone graft is resorbed

Guille et al JBJS Am 1998

- 100% resorption of bone graft with recurrence of lesion

- osteotomy and fixation with reconstruction nail mainstay of treatment

Medical Management

Bisphosphonates

- to relieve pain

Results

Chapuriat et al Bone 2004

- marked reduction in pain

- some resolution / filling in of lesions

Proximal femur

Aim 

- stabilise diaphysis

- prevent coxa vara

- try to wait until skeletal maturity

Management

1.  Valgising osteotomy

2.  Plate (immature) / Reconstruction Nail (mature)

Results

Yang et al Acta Orthop Trauma Surg 2010

- 14 cases with valus osteotomy / currettage / allograft and reconstruction nail

- good restoration of alignment with improvement in LLD 

- no recurrent fractures or progression of deformity

Sabre tibia

Management

Osteotomy + IM nail

THR

Beware large cysts

Giant Cell Tumour

Definition

Benign lesion with a wide spectrum of behavior characterized by stromal cells and giant cells

Epidemiology

Common

- 20% of benign tumours

More common females

- F:M = 1.5:1

- most tumours M>F

Usually patient in 20's

- usually after skeletal maturity

- 3% < epiphyseal closure

Can behave in malignant fashion

Location

Epiphysis

Knee 50% 

- distal femur

- proximal tibia

Remainder

- distal radius

- sacrum

- vertebral bodies (anteriorly like EG compared with ABC/OO)

Clinical

Involved joint has

- dull ache

- effusion

- muscle atrophy

Pathological fracture common

X-ray

Well-defined defect in epiphysis & metaphysis

- no sclerosis around lesion

- sub-articular with extension into subchondral bone

May extend into articular cartilage

- unique ability

Minimal periosteal reaction

± Cortical breach & soft tissue extension

DDx

Brown's tumour / hyperparathyroidism

MRI

Show cortical destruction & soft tissue extension

- soft tissue extension suggest stage 3 aggressive

Bone Scan

Mono v polyostotic

Bloods

Ca++ / Se PO4

- rule out Brown's tumour

ESR 

- Osteomyelitis & EG

Pathology

Two Cell Types

A Multinucleated Giant Cells 

- similar to osteoclasts

- likely reactive

B.  Small Stromal Cells 

- ? the actual tumour 

- probably osteoblast derivatives

Background of fibrous tissue

- normal mitoses usually seen

- areas of spontaneous necrosis (rare for benign tumours)

- thin cortical shell

Campanacci Stagin

Stage I Latent (15%)

Sclerotic Rim

- asymptomatic

- inactive on bone scan

- histologically benign

Stage II Active (70%)

Expanded cortex but no breakthrough

- symptomatic

- often have pathological fracture

- active on bone scan

- histologically benign stromal cells

Stage III Aggressive (15%)

Rapidly growing mass

- cortical perforation with ST mass

- symptomatic

- extensive activity on bone scan

- histologically benign

Malignant

- rare form

- sarcomatous lesion contiguous with benign GCT 

Prognosis

Previously said 10% metastasize

- many of these would now be called MFH

- for it truly to be giant cell have to see typical appearance of GCT in metastasis

Primary malignant GCT better prognosis than malignant change in recurrence

DDx

ABC / UBC

Chondroblastoma

Clear cell sarcoma

Telangiectatic Osteosarcoma

Synovial cyst of OA / Geode

PVNS 

OM (brodies abscess)

Because there are 2 malignant tumours which can mimic

- all need careful staging and biopsy

Management

Staging

Biopsy usually performed

Options

1.  Currettage + bone graft / PMMA
2.  Wide excision + allograft / arthroplasty

3.  Adjuvant treatment

Grade I & II

Management

Currettage and PMMA

- extended curette with high speed burr

- saucerisation 

- bone graft under subchondral bone

- adjuvant PMMA (works by thermal necrosis)

Results

Blackley et al JBJS Am 1999

- treatment of 59 patients with high speed burr and autograft / allograft

- 12% local recurrence

Becker et al JBJS Am 2008

- demonstrated reduced local recurrence with the use of PMMA

Bauer et al JBJS Br 2006

- treatment of recurrences with repeat currettage and PMMA

- 13/15 successful after one treatment, remainder after 2

Grade III & Recurrence

Management

Wide resection & osteochondral allograft / arthroplasty + adjuvant DXRT

Indications

- extensive soft tissue tumour

- extensive cortical destruction / pathological fracture

- joint destruction

Results

Bell et al J Arthroplasty 1994

- fresh osteochondral allograft for distal femur in 16 patients

- 3 revisions and 1 late infection

- 8/13 assessed were good or excellent

Unresectable

DXRT

- i.e. sacral and pelvic GCT

Bisphosphonates

Theory

GCT rich in osteoclast derived cells

Results

Balke et al BMC 2010

- use of bisphosphonates in aggressive primary / recurrent / metastatic GCT

- no increase in size in inoperable tumours

- no recurrences in tumours that had repeatedly recurred

- lung metastasis did not increase in size or number

Recurrence rates

Enneking

- grade 1 = negligible recurrence

- grade 2 = 20%

- grade 3 = 70%

- grade 3 + adjuvant = 20%

Metastases

Lung metastases occur in 2%

- lesions slowly progress ie benign in nature

- usually treat with surgical resection

- consider GCT benign if pulmonary metatasis histologically benign

- regular CXR in patients with GCT

Haemangioma

Definition

Hamartomatous proliferation of vascular tissue

Epidemiology

Commonest tumours in infancy & childhood 

- usually superficial

Types

Capillary

- majority

- small nodules of capillary sized vessels lined by flattened endothelium

- nodules clumped in lobular pattern

Cavernous 

- less common

- usually larger & involve deeper structures

Associations

1.  Klippel Trenaunay Weber Syndrome 

- hemihypertrophy with underlying venous malformations

- secondary to increased angiogenesis

- UL, LL or both affected

- usually unilateral

2.  Maffucci Syndrome

3.  Sturge-Weber

- rare congenital / not hereditary

- often facial capillary malformation

- more extensive hemangiomata

- mental retardation / seizures / hemiparesis  

- hemiatrophy

Site

Cutaneous

Subcutaneous

Intramuscular

Intra-osseous

Clinical

Ache

Limb heaviness

Lesions in the skin - distended bluish discoloration 

Deeper intramuscular lesions present as a tender mass

X-ray

Soft-tissue lesions

- same radiodensity of muscle

Often small calcified nodules / phleboliths

- circular pattern with a radiolucent center (due to recanalization) 

- same as those seen in the pelvic veins of multiparous females

MRI

Exceedingly bright signal 

- due to the high fluid content of the lesion 

CT

Polka dot appearance due to section through the vessels

These lesions often penetrate the bone and have a large soft tissue component

Management

As pain / disability demands

- often observation

Soft tissue Hemangioma

Non-operative

- stockings

- simple analgesia

Operative 

- resection

- embolization

Beware rare cases of malignant change

Intraosseous Hemangioma

Epidemiology

- F:M = 2:1

- incidence increases with age

- 0.8% of 1° bone tumours

- commonest sites are spine (especially thoracic) & skull

X-ray

Characteristic finding is the coarsened vertical trabeculae

Spine 

- honeycomb or corduroy cloth appearance

- in spine this finding is usually sufficient for the diagnosis

Skull 

- spoke-wheel configuration

CT

Characteristic finding is multiple dots "polka dots"

MRI 

Usually bright on T1 & T2 images because of fat content

- areas of trabecular thickening will have low signal intensity

Osteofibrous Dysplasia

Definition

Congenital hamartomatous lesion

- occurs almost exclusively in the tibia or mandible

- striking resemblance to fibrous dysplasia

- thought by many to be a variant of that condition

Location

Anterior cortex of tibial diaphysis

Mandible

Clinical

Young child

Anterior bow or mass in tibia

Pathological fracture common

X-ray

Multiple small radiolucent lesions

Rim of reactive bone

DDx

Adamantinoma

Fibrous Dysplasia

EG

Ewing's

Periosteal OS

Management

Issue

Risk of adamantinoma in lesion

- recommended excision of all lesions

Currettage alone

- 100% recurrence rate

Results

Lee et al JBJS Br 2000 

- review of 16 patients with osteofibrous dysplasia tibia

- 6 treated initially with currettage / all recurred

- treated with segmental excision and management of bone defect

- some small lesions

- others requiring fibular graft or bone transport

- 3 confirmed cases of adamantinoma

- no recurrences

- recommend excision in all cases

Periosteal Chondroma

Definition

Metaphyseal Enchondroma

Site

Arise from the metaphyseal cortex of long bones

- most common in the proximal humerus

Histology

Difficult to DDx from Chondrosarcoma

Masses of cartilage nestling in a shallow crater in the periphery of the cortex

NHx

Don't ossify

- remain as immature cartilage

No malignant potential

- Don't transform into CS

DDx

Juxta-cortical chondrosarcoma

Periosteal osteosarcoma

Unicameral Bone Cyst

AKA

Simple Bone Cyst

Definition

A simple bone cyst is a solitary cavity containing clear fluid

- originating in the metaphysis of growing children

- adjacent to the metaphyseal aspect of the growth plate.

Aetiology

Unknown pathological origin

- likely secondary to venous obstruction / hypertension

- probably not neoplastic

- occurs during growth

Epidemiology

Children

M 2:1

Location

Proximal metaphysis 

- humerus 67% 

- femur 15%

Often immediately below physis

- metaphyseal side

Can occur in os calcis

Types

Active

- adjacent to physis

Latent

- separated from physis by normal bone

Clinical 

Present with pain caused by pathological fracture

- commonest presentation 75%

X-ray

Metaphyseal near physis

- well-defined lucency 

- thin sclerotic rim

- usually central

- thinned cortex with slight expansion

- thin internal septa

- can be multi-loculated

Fallen-Leaf sign 

- with pathological fracture

- "Classic" sign

- pathognomonic because indicates that the lesion has no matrix & is fluid filled 

DDx ABC

ABC

- eccentric (v central)

- width > physis

- can be very difficult to tell

Pathology

Pressure

- they have an arteriolar pressure curve

- cyst pressure is higher than venous pressure

Fluids

- contain high levels of prostaglandins

- contain high levels of alkaline phosphatase

Gross

Thin cyst lining with fine septae

- contains clear fluid compared with ABC

Histology

Thin fibrous layer of CT 

- cells resembles synovial cells

- few multinucleated giant cells

NHx

Tend to become latent

- resolve in adulthood

- may resolve post fracture

Management

Issue

Will eventually heal, but tend to fracture up to 4 times on average

1.  Humerus

- fractures will heal in sling

- must then avoid non contact sports

- difficult to tell child not to play sports for many years

2.  Femur

- want to prevent fracture

- avoid morbidity / deformity

Options

Observe

Inject HCLA

Inject bone marrow aspirate

Currettage and bone graft

Cyst drainage

- cannulated screws

- IM rods

ORIF

Observation

Inactive & small

Aspiration and injection HCLA

Technique

Aspirate initially

- if aspirate blood / treat as ABC / biopsy

- if aspirate fluid / simple cyst

Inject contrast

- ensure not loculated

- if it is, need to inject all parts of cyst

Inject methylprednisolone

- steroid blocks PGE

- methylprednisolone 50 - 200mg

- second needle as vent

Results

Rud et al Orthopaedics 1991

- 11 UBC treated with injection of methyprednisolone

- 2 required second treatment

- 5 cysts resolved completely whilst 6 resolved sufficiently that fracture was no longer a risk

Bone marrow injection

Technique

GA / Aspirate from bone marrow

- inject into cyst under II

Results

Rougraff et al JBJS Am 2002

- 25 cases treated with percutaneous bone marrow aspirate

- combined with demineralised bone matrix

- 5 recurrences

Wright et al JBJS Am 2008

- RCT of bone marrow aspirate v HCLA in 77 patients followed for 2 years

- 42% in the methylpredisolone group healed

- 23% in the bone marrow group healed

Curettage + Bone Graft

Results

Hunt Orthopedics etal 2009

- 21 proximal humeral cysts

- 75% union rate

Cyst drainage

Concept

- venous hypertension cause of cyst

- if allow cyst to drain, will heal

Options

- cannulated screw into lesion

- TENS nails humerus

- IMN femur

Results

Linhart et al Orthopedics and Traumatology

- 21 proximal humeral cysts

- distal to proximal flexible nails

- 95% union rate

Hou et al JBJS Am 2010

- humeral cysts

- 11/12 healing with currettage / synthetic bone graft / cannulated screw

Specific Regions

1.  Humeral Unicameral Bone Cysts

Treat fractures non operatively in sling initially

- need treatment if debilitating

Options

1.  Non operative / avoid contact sports and wait

2.  Injection HCLA

- minimally invasive, perform in OT

3.  Percutaneous TENS nails

2.  Proximal Femur Unicameral Bone cysts

Pathological fracture

- treat in traction / spica if minimally displaced or very young

- otherwise paediatric sliding hip screw

- reconstruction nail if > 15 years

Non fractured but high risk

- trial injection

- paediatric hip screw if < 15 with bone grafting

- IMN if > 15

Bone Infarct

Epidemiology

In caisson workers / divers

Sickle cell anemia

Long term steroid

Aetiology

May sometimes be a degenerating lipoma of bone

DDx

Chondroblastoma / Chondrosarcoma

- if in metaphyseal region

Enchondroma

Bone island

Bone Scan

No increased uptake

Histology

Mineralisation of necrotic marrow elements

Prognosis

MFH may arise from long standing bone infarcts

Enchondroma

Definition

Benign intramedullary cartilage lesion

Aetiology

Enchondroma are presumed to be remnants of hyaline cartilage

- derived from the epiphyseal growth mechanism that failed to undergo enchondral ossification

Epidemiology

10% of benign bone tumours

Young adults

Stop growing in adults and calcify

Malignant transformation 

Rare

- enchondroma in hands and feet always benign

- benign looking enchondroma located centrally may be malignant

Age 

- in general not malignant prior to maturity

Bone scan not helpful

Histology not helpful

Location

Intramedullary

Start near physis (metaphyseal) but may become diaphyseal

Involves any bone formed by endochondral ossification

- especially tubular bones of hands & feet

- 50% in hands, especially phalanges

- 10% in feet

- also common femur, humerus & ribs

Can have periosteal chondroma

- surface long bones

- calcified matrix

- well demarcated cortical defect

Clinical

Usually incidental finding

- may be patholological finding

X-ray

Intralesional calcification in adults

- especially in long bones

- punctate, stippled calcification and broken rings

No periosteal reaction

Suspicious Lesion (5)

1. X-ray appearance

- scalloping (endosteal erosion)

- periosteal reaction

- fluffy calcification

2.  Size > 6-10 cm rarely benign

3.  Peripheral vs central 

- central pelvis / shoulder girdle more concerning

4.  Age - malignancy rare <20

5.  Solitary vs Olliers

- benign more cellular in Olliers

Bone Scan

Usually increased uptake

MRI

Pathology

Composed of masses of hyaline cartilage without characteristic architecture

- typically bland cartilage

- no pleomorphism / anaplasia / hyperchromasia

- hand lesions tend to look more hypercellular & pleomorphic

Can be very difficult to distinguish between low grade chondrosarcoma and enchondroma

DDx

Long Bone with Intralesional Calcification

1.  Enchondroma

2.  Bone infarct 

3.  Chondrosarcoma

Phalanx

- epidermoid inclusion cyst

- glomus tumour

Staging

Plain radiograph

- biopsy usually not required

Management

Options

1.  Observation

Biopsy

- enlarging

- becomes painful

2.  Prophylactic Resection

Doesn't require prophylactic resection because

A.  Malignant transformation very rare <1%

- usually in pelvic or shoulder girdle

B.  Transform to chondrosarcomas

- low-grade, slowly growing and painful

3.  Hand fracture through enchondroma

Allow to heal non operatively if possible

Curettage and bone graft once united

Enostosis

AKA

Bone island

Definition

Hamartomatous lesion 

- island of mature cortical bone found in the midst of normal cancellous bone 

Epidemiology

>10

M=F

Clinical

Asymptomatic x-ray finding (usually in adolescents)

X-ray

Sharply-circumscribed cortical densities

- usually round or oval in shape with smooth, regular borders

- sharp / narrow zone of transition from lesion to cancellous bone 

- no evident reaction to the process

Range in size from a few mm to several cm

- more commonly less than 1 cm in diameter

CT 

Even cortical texture

Management

Observation

Osteopoikilosis 

Multiple bone islands

- sclerosing skeletal dysplasia

- AD inheritance

- hips / pelvis / sacrum / femur / humerus

- characteristically periarticular

- lesions asymptomatic and cold on bone scan

- malignant transformation extremely rare

Melorheostosis

Epidemiology

Rare, non-hereditary lesion

- 1: 1 000 000

M = F

Apparent in early childhood and even in the first few days of life

About 50% of persons affected will develop the symptoms by 20 years of age

Aetiology

Unknown

Theory 

- lesion arises from an abnormality of the sensory nerve of the affected sclerotome

- sclerotome is a zone of the skeleton supplied by an individual spinal sensory nerve

- represents a basic unit of vertebral embryonic development.

Clinical

Pain, joint stiffness, and progressive deformity

- mainly the bones of the extremities and pelvis

LLD, deformity

Joint contractures

- secondary to extraosseous bone formation

Can cause spinal stenosis

Can have extensive ST masses, which can ossify

X-ray

Sclerotic lesions of bones 

- undulating cortical hyperostosis

- look like wax dripping down the side of a candle

Bone Scan

Increase uptake

MRI

Heterogenous

- mix of osseous, fibrous, adipose, cartilage

Biopsy

Variable degree of marrow fibrosis

- with markedly irregular bone with mixed areas of lamellar and woven bone

- mixture of osteocartilagenous, fibrovascular, and adipose tissue is seen in the soft tissue masses

NHx

The clinical course is slowly progressive

Severe symptoms may require treatment by sympathectomy or even amputation

Isolated cases of malignancy have been reported in association with melorheostosis

- one osteosarcoma and one malignant fibrous histiocytoma

Multiple Enchondromas

Multiple enchondroma occur in two circumstances

1. Ollier's

-  distributed symmetrically in an extremity

2. Maffucci's syndrome

- randomly distributed throughout the skeleton

- in association with hemangiomas

Ollier's Disease

Site

Enchondromas symmetrically distributed through an extremity

Usually unilateral and monostotic

Epiphyseal, metaphyseal or diaphyseal

Inheritance

Not heritable / embryonal disorder

Problems

1.  Often associated deformation of growth

- LLD

- bowing wrist

- bowing elbow

2.  Malignant transformation

- 25% at 40 years

Maffucci's Syndrome

Clinical Features

Multiple enchondromas 

- randomly distributed

- associated with hemangiomas

Problems

1.  100% risk of malignant transformation 

- usually long latent phase

- 30 - 50 years of age

2.  Associated with other tumours

- visceral carcinoma

3.  Cutaneous hemangiomata

- bring diagnosis to attention

4.  Skeletal deformity

- short tubular bones hands & feet

- long bones of UL / LL

- one side of body usually more severe

- palpable mass

- LLD

- bowing of forearms

- varus / valgus of legs

Management

Osteotomy through lesion to correct angulation

Epiphyseodesis or limb lengthening

Curettage & grafting of large lesions interfering with function

Need lifetime vigilance for tumour transformation

Multiple Hereditary Exostosis

AKA

Diaphyseal Aclasis / Multiple Osteochondromas

Definition

Heritable skeletal dysplasia

Epidemiology

AD with variable penetrance (96%)

Malignant Transformation

Incidence of malignant transformation much higher 

- 10% overall

- 1 % / year

Chondrosarcoma (CS) > Osteosarcoma (OS)

Secondary CS has better prognosis than primary CS prognosis

Danger areas / central

- pelvis

- scapula

- proximal humerus

- proximal femur

- spine

Clinical

Mildly short stature

Nerve compressions

Upper Limb

Scapular involvement (winging)

Forearm involvement

- ulnar deviation of wrist

- loss of pronation / supination

Lower Limb

LLD

Valgus knees

Valgus ankle

CPN compression

X-ray

1.  Coxa Valga

- neck short & broad

2.  Genu valgum

3.  Ankle valgus

- fibular shortening with valgus distal tibia

- wedge-shaped distal tibial epiphysis

- leads to valgus talar tilt in abnormal mortise

4.  Forearm 

- ulnar shortening with radial bowing

- ulnar deviation of wrist

- radial head dislocation

Histology

Exostoses tend to be more disorganised with bosselated cartilage cap

Management

Principles

Excision of symptomatic osteochondromas

Removal of suspicious lesions

Sites

Forearm

Most disability 

- maybe little functional loss

- pronation / supination decreases with age

No evidence that OT will improve function

- distal radial osteotomy / hemiepiphyseodesis

- lengthening of ulna

- excision of local osteochondromas

Ankle

Chin et al JBJS Am 2000

- demonstrated that early removal in full of osteochondroma

- allowed remodelling of deformity

1.  Guided growth

- slow growth medially / screw or 8 plate

- allows lateral fibular growth to correct valgus

2.  Supramalleolar osteotomy / Ilizarov correction

- deformity correction

Knee

High incidence of valgus tibial deformity

Case reports of popliteal pseudoaneurysm

Nora's lesion

It was described in 1983 by Dr. Nora, and is sometimes called Nora's disease or Nora's lesion

Definition

Bizarre parosteal osteochondromatous proliferation 

Epidemiology

Rare lesion 

- occurs most commonly in the hands and feet

Adults in their 20's and 30's

Males = Females

Site

Most common in the hands 

- followed by the feet

- long bones (commonly of the upper extremity)

- skull, jaw

Hands

- proximal and middle phalanges

- metacarpals

NHx

Grows rapidly

- aggressive features on imaging 

Clinical

Mildly painful mass 

- seems to increase in size over many weeks or a few months

- usually no history of trauma

X-ray

Bony mass

- well defined margins 

- seen to be applied to the surface of the bone

- it may project into the soft tissues

- lacks the characteristic orientation away from the nearby physis that is seen in osteochondromas. 

Wide base

- may appear pedunculated

Matrix

- mature, trabeculated bone

CT

Osteochondromas

- cortex and medullary cavity of the bone is continuous with the cortex and medullary cavity of the lesion

BPOP / Nora's

- cortex and medulla not contigous with cortex

- no cartilage cap

MRI

Typical tumour picture

- high SI on T2

- low SI on T1

No cartilage cap

DDx

Parosteal / periosteal OS

Pathology

Gross 

- nodular surface covered with glistening cartilage.  

- bone in the lesion has a distinct blue tint 

- The cut surface of the lesion bleeds freely

Histology

Very cellular cartilage

- proliferation of bizarre fibroblasts

- disorganized bone with spindle shaped fibroblasts in the intertrabecular spaces

Confusion with 

- chondrosarcoma

- fibrosarcoma

- low grade parosteal osteosarcoma

- conventional osteosarcoma.  

NHx

Lesion is benign 

Management

Wide excision

- limits local recurrence

Recurrence

- may recur locally in as many as 50% of cases

- seen from 2 months to 2 years after surgery

Osteoblastoma

Epidemiology

Uncommon

< 1% Primary bone tumour

Young boys

- second decade

Location

Similar to OO

Spine 30%

- especially posterior elements

Long bones 35%

Clinical

Back or limb pain

- pain less severe than OO

- not dramatically relieved by aspirin

Limp

Scoliosis

X-ray

Spine

- difficult to see

- irregular cortex

- sclerotic or loss of pedicle

- enlargement of spinous process

Long Bone

- less diaphyseal occurrence than OO

- more common meta-diaphyseal

- large faintly radiolucent lesion

- thin reactive rim

- may be expansile

CT 

Demonstrates spinal lesion well

- bone expansion

- intralesional stippled ossification

Bone Scan

Uptake +++

DDx

Osteoid osteoma

- < 2 cm

Pathology

> 2cm diameter

- less reactive rim

- otherwise identical to OO

- osteoid

Can be difficult to differentiate from OS 

- may also see changes of ABC

NHx

On rare occasion have acted aggressively

- bone destruction & soft tissue extension

- however don't metastasise

Management

Options

1.  Excision with wide margin

- preferred

2.  Extended curettage

- indicated in spine

- recurrence not uncommon, & difficult to treat

3.  Radiofrequency ablation

Osteochondroma

Definition

Outgrowth of benign cartilage from bone

Epidemiology

50% of benign bone tumours

- single lesion in 90% 

Aetiology

1.  Multiple

Tumour suppressor gene

- family of tumour suppressor genes involved

- have been identified in chondrosarcomas

- 2 hit model of tumourigenesis

Both alleles must be mutated for an osteochondroma to form

- if inherit an abnormal allele need other allele to undergo mutation to form osteochondroma

2.  Single

? Secondary to injury of growth plate

- defect in Perichondral Ring La Croix

- results from herniation & separation of fragment of physis through the periosteal bone cuff 

NHx

Grows by endochondral ossification of enlarging cartilage cap

- stops at maturity

Malignant Transformation

Low-grade Chondrosarcoma

- isolated lesion < 1% 

- more common with central lesions

Suspicious features (6)

1.  Growth after maturity

2.  Hot bone scan (can be from overlying bursa)

3.  Increased thickness of cartilage cap on CT

- > 1-3 cm (Enneking) 

4.  Pain

5.  Pathological fracture

6.  Disappearance of calcification

Enneking

- when the rim of cartilage in an adult exceeds 25 millimeters, it is highly suggestive of malignant transformation

Location

Any bone formed by endochondral ossification

Arises from cortex of long bone adjacent to physis

Most common 

- around knee 

- proximal humerus

Clinical

Commonly noticed during adolescent growth spurt

Symptoms of mass lesion

- pain & tenderness

- decreaed ROM

- compression of NV structure

X-ray

Protuberant bony lesion

- arising adjacent to physis

- directed away from joint

- cortical bone continuous

- marrow space continuous 

- cartilage cap may be calcified

Types

1. Pedunculated / exostosis

2. Sessile

CT

Cortex and medullary cavity of normal bone contiguous with osteochondroma

MRI

See cartilage cap

- iso-intense with hyaline cartilage

Pathology

Gross

- looks like cauliflower

- surface covered with irregular cartilage

- cartilage usually 3-5 mm adults

- 5 - 10 mm children

- bone has cortex & medulla 

Histology

- cap resembles disorganised physis

- irregular shaped underlying trabecular bone

- may contain calcified cartilage matrix

DDx 

Juxtacortical OS / CS

Periosteal Chondroma

Osteoma

Management

Surgical Indications

1. Excise painful mass

2. Tendon / NV impingement

3. Restore joint motion

4. Correct deformity

5. Biopsy suspicious lesions

6. Central / pelvis / scapula 

- due to higher malignant transformation rate

Osteoid Osteoma

Definition

Benign, bone-forming neoplasm

- characterized by a small nidus of neoplastic tissue

- surrounded by a wide zone of mature, reactive bone

Epidemiology

10% of benign bone tumours

Age 5-25

M:F 2:1

Aetiology

Unknown

- thought may be glomus tumour of bone

Pain secondary to prostaglandin production

Site

Intra-cortical position usually

60% femur, tibia

- usually at end of diaphysis 

- cancellous or cortical 

Posterior elements spine

Clinical

Characteristic pain

- intense, unrelenting ~ toothache

- night pain

Relief by aspirin / salicylates

- dramatic

- often within 30 minutes of one dose

May be worsened by ETOH

Scoliosis

Joint effusion if juxta-articular

NHx

Gradual resolution with time

X-ray

A.  Medullary OO

Four Diagnostic Features / 50% show all 4

1.  Sharply round or ovoid

2.  < 1cm

3.  Homogenously dense centre

4. ~ 1mm peripheral radiolucent zone

B.  Intra-cortical OO

- area of dense bone

- often fusiform-shaped

- central nidus usually not seen

- mimics stress fracture

Bone Scan / SPECT

Uptake +++

Useful to locate lesion especially in spine

CT 

Thin slice CT best investigation

- lucent nidus

- surrounding dense bone

MRI

Pathology

Gross

Lesion is nidus

- < 1 cm diameter

- cherry red & granular

- dense reactive bone peripherally

Histology

Immature trabeculae enveloped by prominent osteoblasts / clasts

Lucent zone

- surrounding zone of hyperaemic fibrous tissue

- thin lacelike woven bone seams

- AKA osteoid seams 

- haphazard

- numerous vascular channels & rich nerve fibres 

- osteoblasts & giant cells surround

- no chondroid elements

No haemopoietic elements in vascular channels

Osteoid surround by vascular fibrous stroma

DDx

Cortical

- infection

- stress stress fracture

- parosteal OS

- osteoblastoma

Medullary

- VINDICATE pneumonic

Management

Non-operative

NHx

Can resolve

- ? spontaneously heals 

- takes a long time

- NSAID for pain relief

- doesn't progress to cancer

Operative

Goal is to remove the nidus

1.  En Bloc Excision

Gold standard

- ensures all of lesion excised

- weakens bone

- risk of fracture especially with lesion in femur

- need bone graft & protection

- send for intra-operative fresh frozen section to ensure have excised OO

2.   "Burr Down" Technique

Technique

- intraoperative CT guidance

- direct incision over lesion

- shave cortex off with high speed burr to reactive bone 

- scoop nidus out once hit hypervascular zone & sent for FFS

- burr 2mm zone out

- can leave strong reactive bone behind

3.  Percutaneous Guided Reaming

CT guided in xray suite

- doesn't produce tissue for histology

4.  Radiofrequency Ablation

Technique

- GA

- introduce electrode under CT

- can take tissue for histology

- radiofrequency

- increase temperature for 6 mins to 90^o

Contraindication

- spine

- risk thermal injury to spinal cord / nerve roots

Results

Rosenthal et al JBJS Am 1998

- equal rates recurrence (9%)

- no complications

- increased patient satisfaction

- drastically reduced in patient stay

Osteoma

Definition

Benign, hamartomatous bone-forming lesion arising from the surface of the affected bone

Aetiology

Excrescence of dense bone which arises from the surface of bones formed by intra-membranous ossification

Epidemiology

Age 25-50

M=F

Site

Skull or mandible

- classically

Shafts of long bones

- often see posterior femur

- similar location to parosteal OS

"flat bones and tibial diaphysis"

Pathology

Gross

- dome-like outcropping

- dense bone

- covered by a capsule confluent with the periosteum

Histology

- heavy trabecular bone

- matures into dense cortical bone 

- over-maturation 

- many small haversian canals

- some canals are obliterated 

DDx

Parosteal osteosarcoma

Exostosis

Prognosis

Active stage 2 lesion 

- never goes to 3 or 1

Association

Gardner's Syndrome

Management

Intracapsular or marginal excision 

- removing the lesion from the surface of the bone

- negligible risk of recurrence

- wide en bloc excision not necessary

Background

Aim 

The identification of skeletal metastasis & fixation prior to fracture

Incidence

50% of new cancer cases have metastasis

- 1% have pathological fracture

- increasing with more aggressive palliative care

Reasons to Avoid Pathological Fracture

Life expectancy after diagnosis

- 40% at 6/12

Non-operative treatment poor

- morbidity

- non-union

Improves survival 

- 20%

More difficult to manage once fractured

Clinical presentations

1.  Metastasis with unknown primary / rare

2.  Pathological fracture

3.  Metastasis with known primary / commonest

Indications for OT

1.  Life expectancy > 2/12

2.  Tolerate major OT

3.  Stable fixation possible

Origin

Bone seeking malignancies

- 80% PBL

- prostate, breast, lung

- occult metastasis usually breast & prostate

Also Kidney, Thyroid & GIT

- 20%

- remember the hexagon

- with malignant melanoma & lymphoma in centre

Site 

80% axial 

- earliest

20% appendicular 

- usually proximal especially proximal femur +++

Mechanism of dissemination

1.  Haematogenous 

Cells carried on fibrin raft

- multiple steps

- cross many tissue layers

- tissue preference

2.  Lymphatic 

- renal cell

- OS

3.  Direct 

- rare

4.  Iatrogenic

Bone Reponse to Tumour 

Lytic / Sclerotic / Mixed

Purely lytic

- lung 

- kidney

- breast

- thyroid

- GI

- neuroblastoma

Mixed 

- breast

- prostate

- lung

- bladder

Blastic

- prostate

- breast

- bladder

- GI

- lung (oat cell)

Bone Destruction

1.  Osteoclast mediated 

- 2° local factors eg TNF

2.  Direct destruction 

- via enzymes

Pain 

75% of metastasis

Cause

1.  Stimulated nerve ends by direct invasion of tissue

2.  Periosteal stretching

3.  Fractures

4.  Nerve irritation

X-ray

Need > 50% bone loss to see

Remember to xray entire bone

- especially NOF fracture

- need to bypass all lesions

Bone Scan

Most sensitive screen

False negative ~10% 

- Myeloma / EG / Melanoma / RCC

- overwhelm osteoblasts via Osteoblast Inhibiting Factor

Management

Mirels Prediction system for Pathological Fracture

Clin Orthop 1989 

- 38 patients treated with DXRT without surgery 

- most breast cancer

- developed scoring system

- predicts post DXRT fracture risk in preDXRT long bones

- risk of fracture within 6 months 

- irradiated without fixation

Four risk factors

                1             2             3

Site:     Upper       Lower      Peritroch

Pain:      Mild          Mod       Functional

Lesion:  Blastic      Mixed        Lytic

Size:     <1/3       1/3-2/3       >2/3

Score < 7 irradiate safely

- < 4% chance fracture

Example

- large lytic lesion in proximal femur

- will score 9 immediately

Scores

8     - 15% chance # post DXRT

9     - 33%

10   - 82%

11   - 96%

12   - 100%

Mortality 

After pathological fracture

- lung Ca = 100% mortality 6/12

- breast Ca = 50% mortality 6/12

Median survival metastatic disease

- 50% survive 6/12

- 30% survive 1 year

- lung 6/12

- breast 18/12

- prostate 24/12 

Worse if

- hypercalcemia

- lung mets

- paraplegia 

Management

Aims

1. Appropriate patient selection

Need to live longer than time for recovery from the operation (> 2/12)

Poor prognosis

- lung

- visceral & bone metastasis

- short interval between diagnosis & metastasis

2. Reconstruct so that FWB immediately

Overall union rate is 35%

- <15% for lung & myeloma

3. Address all involved areas in the bone

4. DXRT post-op

- entire femur should be irradiated after reaming

- patients that have DXRT have improved function & lower re-operation rate

Metastasis survival predication

Prediction of prognosis

- score correlates to prognosis

- six parameters with a total score of 0 to 12

Parameters

General condition according to Karnofsky's performance status

2 points for 80-100%

1 point for 50-70%

0 points for 10-40%

No of °spinal bone mets on scan

2 points for none

1 point for 1-2

0 points for 3+

No of vertebral metastasis

2 points for 1

1 point for 2

0 points for 3+

Metastasis to the major internal organs including lungs, liver, kidney and brain

2 points for no met

1 point for operable lesion

0 points for inoperable lesion

Primary site

2 points for thyroid, breast, prostate & rectum

1 point for kidney & liver, uterus, bladder, gallbladder or unidentified

0 points for lung & stomach

Spinal Cord Palsy

2 points for Frankel E

1 point for Frankel C or D

0 points for Frankel A or B

Prediction

Average period of survival

Score of 9 to 12 > 12 /12 

Score of 6 to 8 - 3 12/ 12

Score of 0 to 5 < 3/12

Principles

Remember principles are same as normal fracture fixation

- fixation will eventually fail if fracture does not unite

Healing is slower than normal bone

- irradiation reduces this even more

- 50Gy >14 days after surgery doesn't produce notable increase of non-union

Goal is to obtain union

- avoid fracture during procedure

- preserve soft tissue envelope

- rigid internal fixation

- if large lesion >75% of cortex augment with PMMA

Preoperative Issues

Pre-op embolize vascular tumours 

- renal cell

Nutrition 

- consider hyperalimentation

Hypercalcaemia 

- from tumour / fracture / metastasis

- stones, bones, abdo moans (pancreatitis), psychic moans

- treat with bisphosphonates -> inhibit osteoclastic activity

High uric acid levels 

- prophylaxis against gout

Marrow suppression

- from chemotherapy or mets

- risk infection and excessive blood loss at time of surgery

DVT prophylaxis

DXRT

Post-op DXRT for local control

- start Day 14

- 30 Gy / 3000 Rads in fractionated doses

There is a period of transient osteoporosis after DXRT in first 2 weeks

- increased fracture risk by 25-40%

- also increased infection rate

Healing

Harrington 1986 

65-85% metastasis will heal with radiotherapy if no fracture

- almost normal bone structure takes 4-6/12

Healing of pathological fracture without fixation very poor

- non-union 65-80%

With prophylactic fixation & 2200 rads

- 96% remission rate (of which 26% is permanent)

- 94 % bone healing

- 86% union of pathological fracture with interlocking fixation 

Fixation Technique

Harrington 1986

- aim to span diseased segment with biomechanically strongest construct

- intramedullary best 

- prosthetic replacement has better results than ORIF

- bone grafts not effective with post-op DXRT

PMMA 

Excellent

- improved results in both animal & human studies

- increased construct strength / bending strength

- improves hardware fixation to bone / improves screw hold

- better pain relief

- immediate weight bearing

- not effected by DXRT

Metastasis with Unknown Primary

Likely Origin / Hexagon / PBBLTK

                    Thyroid     Breast      

Lung           MM  Lymphoma         Kidney        

                    Bowel            Prostate

Most common site for "unknown primary" 

- lung 63%

- kidney 10%

Most common "known primary"

- breast and prostate

Plan 

1.  Medical History

- previous malignancy

- symptoms for most likely primaries (above)

- history smoking, coughing up blood

- breast lumps

- blood in urine

- bowel disturbance / blood

- fevers / temps / generally unwell

2. Physical exam

- breast in women

- prostate in men

- lymph nodes 

- thyroid in neck

- skin

3. Plain X-ray 

- bone involved

- any other bones with pain

- CXR

4.  Routine bloods

- FBC ELFT

- ESR / CRP

- TFT

- PSA

- Se electrophoresis / BJ urine

- Ca, PO4, Alk Phos

- LDH

- blood film / suspect leukaemia

5. Bone scan

- polyostotic / monostotic

6. CT Chest/ Abdo / Pelvis

- lung / bowel / renal

7.  Biopsy of most accessible lesion

Multiple lesion

- biopsy most accessible

If isolated bony lesion

- need to treat as primary bone tumour

- stage locally / MRI

- consult with local orthopaedic oncology unit

- discuss biopsy procedure

Bone marrow biopsy

- lymphoma / myeloma

Seminal Paper

Simon et al JBJS Am 1993

- 40 patients prospective study

- allows identification of 85% 

- lab values non-specific in all cases (myeloma excluded)

- history and examination found primary in 8%

- CXR found 43% of primary

- most important finding was benefit of CT

- 75% of primary diagnosed on CT chest, abdo & pelvis

- biopsy diagnosed 8% and confirmed in 30%

Specific Management

Subcapital Femoral Neck Metastasis

Fractures

Principle

- do very poorly with fixation

- hemiarthroplasty or THR

- stem should be 2.5 cortical diameters beyond any area of weakness

- THR if acetabulum involved

Lane JBJS 1980 

- 167 patients post proximal replacement

- median life expect 5.6m

- none had mechanical complications

- all walked

Prosthesis

THR

Proximal femoral prosthesis

- indicated for extensive metastasis

- expensive / high dislocation rate due to loss of abductor mechanism

- hemiarthroplasty better to avoid dislocation

Intertrochanteric Metastasis

Lesion only

Options

- either pin & plate / reconstruction nail

- depends if further lesions in femur

- augment with PMMA

Fracture / Very Large Lesion

- calcar replacement prosthesis

Subtrochanteric Metastasis

Management

Reconstruction nail preferred

- place distal vent prior to reaming

Acetabular Metastasis

Harrington classification

Type I

- minor cavitary defect

- medial and superior walls intact

- standard cemented cup

Type II

- major deficit in medial wall

- rim intact

- wire mesh to contain cement or protrusio ring

Type III

- massive deficit in lateral wall & superior cortex

A.  Flexible threaded Steinmann pins & protrusio cup

- anterior column inserted antigrade through iliac crest

- posterior column inserted retrograde thru acetabulum while palpating sciatic notch & SIJ thru iliac crest incision

B.  Saddle prosthesis

Femoral Diaphysis 

Management

IM Nail

Supracondylar Femur 

Options

- Screw plate / Blade plate

- retrograde nail  

- modular knee prosthesis

Proximal Humerus 

Options

- ORIF

- tumour prosthesis

RCC

Humeral shaft 

Operative v Non operative

Surgical Options

- locked IM nail

- PMMA + plate (probably more secure with less pain)

Weiss et al JBJS Br 2011

- 63 patients

- 11% reoperation rate

- good return of early function without pain

Dijkstra Eur J Surg Oncol 1996

- 38 cases, half IMN, half plate + cement

- higher rates of pain relief with ORIF and cement

Proximal tibia

ORIF

AV Malformations

Elasto Fibroma Dorsi

Condition

Strange scapular tumour

- typically bilateral 

- occurs in lat dorsi

Complain of lump which appears around scapula

Imaging

Looks like muscle on CT

Behaviour

Benign

Histology

Shows marked amount of elastin

Fibromatosis

Aggressive Fibromatosis / Desmoid Tumour

Benign aggressive 

- most serious of all benign STT

Types

1.  Intra-abdominal 

- association familial polyposis coli & Gardner's syndrome

- aggressive infiltration

- death from retroperitoneal extension

2.  Extra-abdominal 

Non-metatasizing locally aggressive STT

- often invasive locally

- similar to low grade fibrosarcoma

Classically arise chest wall

- also limbs, head & neck

2 types

- superficial fibromatosis - palmar & plantar

- deep fibromatosis

Epidemiology

F > M 

Average age 40 years

Presentation

Mass most common

Stiff joint

Neurological compression

Mostly proximal - axilla & groin

Pathology

Gross

Firm mass with white hard cut surface

- may infiltrate local muscle

Histology

Spindle shaped fibroblasts with plump nuclei & mildly eosinophilic cytoplasm

- often arranged in parallel rows

- separated by variable but large amount of collagen

- may have high degree of cellularity

- very few mitoses & no necrosis

Can infiltrate skeletal muscle at periphery

Management

Wide resection + DXRT

80% success

Recurrence

Intralesional excision 

- 90% recurrence

Wide excision 

- 50% recurrence

Tumour resection margin

- best prognosticator

- tumour margin clear > 2 mm

Radiotherapy alone 

- used for inoperable tumours & after debulking 

Ganglion

Definition

Cystic structure lined by a mature capsule of dense fibrous tissue

- contains thick viscous fluid with a high mucopolysaccharide content

- fluid is a myxoid degeneration of synovial fluid

Epidemiology

Most common in young females

- peak age 15-30

- F:M = 3:1

Most common tumour in hand (2/3)

Aetiology

Unclear

Numerous theories

- synovial herniation through capsular defect with development one way valve

- synovial rest

Pathology

Development

- in early stages, communicate with cavity of tendon or joint

- with time, connection obliterated by fibrous tissue

- become completely enclosed

- fluid becomes inspissated (thickened / dried)

Gross

- thin-walled cyst

- may be multiloculated

- easily separated from surrounding soft tissues

- contents clear, viscous & jelly-like

- arthrogram usually demonstrates joint communication

Histology 

- wall of paucicellular fibrous connective tissue

- no true epithelial or synovial lining

- contents consist of hyaluronic acid / plasma proteins

History

Most commonly present with cosmesis issue

Appears suddenly or develop slowly

Subside with rest & enlarge with activity

Location

Most common around hands & feet

Increased incidence with

- RA

- OA (eg Meniscal cyst)

Management 

Non-operative

Aspiration of cyst

Rupture of wall with multiple needle punctures

- instillation of xylocaine & celestone

- 50% recurrence

Operative

Excision

GA & tourniquet

- excision of lump in full

- attempt to locate and tie off neck

- may excise segment of capsule

Lipoma

Definition

Benign adipose tumour

Epidemiology

Most common mesenchymal neoplasm

- arise from normal fat

- appears during adulthood

Clinical

80% subcutaneous

- shoulder girdle & proximal thigh most common sites

- well circumscribed mobile, round masse

Condition

Durcen's Disease 

- multiple lipoma subcutaneous disease

MRI

Same signal intensity as surrounding fat

Classification

Divided into 5 subtypes 

1.  Simple lipoma

2.  Spindle Cell Lipoma

3.  Pleomorphic Lipoma

4.  Intramuscular & Intermuscular

5.  Angiolipoma

1.  Simple Lipoma

Incidence

- most common mesenchymal tumour

- tumour of adulthood usually > 40

- multiple in 5%

- 80% of all lipomas

- shoulder & proximal thigh common site

Macroscopic

- well circumscribed

- round to ovoid masses

- 4-10cm long

- homogenous pale to bright yellow on cut surface

Microscopic

- same as normal fat

- sheets of mature fat cells ovoid to round in shape

- contain single fat droplet 

- peripheral nucleus 

- capillary like vessels are occasionally seen between lobules

- areas of myxoid change or dense fibrous trabeculae are sometimes seen

2.  Spindle Cell 

Painless firm nodule on neck & shoulder in middle aged men

Macroscopic

- encapsulated with a delicate fibrous membrane

- arise within the subcutaneous tissue

- on section may have white to grey myxoid areas

Microscopic

- mature fat cells

- variable number of benign spindle cells

- the spindle cells are uniform & arranged in parallel

- mitotic figures are rare

- occasional lipoblasts occur

3.  Pleomorphic Lipoma

Rare

Microscopic

- similar to spindle cell

- has pleomorphic fat cells 

- multinucleated giant cells instead of spindle cells 

4,  Intra & Inter Muscular Lipoma

Macroscopic

2 types

- well defined fatty tumour or

- ill defined infiltrative lesion

- unlike superficial lipomas these variants often don't have a capsule

- tend to encircle nerves

Microscopic

- characterized by sheets & nests of mature adipose tissue insinuating between bundles of muscle fibres

- the fat cells are not atypical, & lipoblasts never occur

5.  Angiolipoma

Atypical Lipoma

Microscopic

- have areas of fibrous, myxoid or other connective tissues

- often see secondary changes of calcification & haemorrhage etc

- true lipoma never becomes malignant

An atypical lipoma can't be differentiated from well differentiated liposarcoma

- often become large & mimic soft tissue sarcomas

Treatment

Wide margin

- clinical setting & an adequate tissue sample are required to differentiate liposarcoma

Neurilemmoma

Definition

Schwannoma

- benign tumour of nerve sheath

Epidemiology

Less common than neurofibroma

- occurs in adults

- can occur along any peripheral nerve

- also can occur along a nerve root

Usually a large nerve

More common in forearm

Seen in NF 2 

- acoustic Schwannoma

Gross Pathology

Usually located eccentrically within nerve 

- compared with NF which are fusiform swellings of the nerve

Well encapsulated

- capsule consists of epineurium

- bulges from originating fascicles & pushes aside adjacent fascicles

Histology

Contain spindled Schwann cells

Arranged in alternating hypercellular (Antoni A) & hypocellular (Antoni B) regions

Antoni A

- spindle cells form short intersecting fascicles

- whorling pattern with palisading nuclei

- nuclei pallisade & align into columns

- Verocay Bodies - adjacent parallel columns of nuclei separated by fibrillar cell processes

Antoni B

- spindle cells twisted & haphazardly arranged

- separated by abundant myxoid ground substance

- may be dilated blood vessels

- more loosely arranged myxoid tissue

Immunohistochemistry

Positive

- Vimentin

- S 100 strongly +ve

- Leu-7

Negative

- Glial fibrillary protein

- Keratin

Loss of genes on Chr 22

History

Painful tender lump

- altered sensation or weak uncommon

- usually along flexor surface

- can increase & decrease in size

Examination

Soft cystic lump

- mobile transversely but not longitudinally

- strongly positive Tinel's

MRI 

Show lesion on nerve periphery

Compared with NF which is in centre of nerve

Management

Operative excision

Usually removed easily

- open capsule & enucleate with little or no injury to nerve fascicles

- shelling pea from pod

If uncertain of diagnosis, obtain fresh frozen section

Malignant degeneration occurs, but rare

Neurofibroma

Definition

Benign tumour of nerve & sheath tissue

Epidemiology

Most common benign nerve sheath tumour

- associated with NF 1

- usually arises from small cutaneous nerves

Classification

1.  Localised

- most common type

- usually solitary (90%) with no genetic association

- nil malignant transormation

Originate from very small branches of cutaneous nerve

- non encapsulated

- consist of twisted spindle cells arranged in fascicles

- accompanied by wire-like bundles of collagen / myxoid stroma

2.  Diffuse

Uncommon

- proliferation of spindle cells, collagen & stroma

- permeates subcutaneous tissue & dermis

3.  Plexiform

Pathognomonic of NF 1

Massive expansion of nerve by proliferating tumour cells

- may involve small cutaneous nerve

- ill-defined nodule

- may originate in large nerve

- elephantiasis or gigantism

10% malignant transformation

Pathology

Contain proliferation of

- schwann cells

- perineural cells

- fibroblasts

Looks like bland but collagen rich fibrous tumour

- small to moderate amounts of mucoid material

- not encapsulated

S-100 stain

- far less intense than in neurilemmoma

DDx

Schwannomas / neurilemmoma

- contain only Schwann cells

Clinical

Localised - painless, soft, mobile

Diffuse - plaque-like cutaneous mass

Plexiform

- ropey redundant mass

- feels like a bag of worms

- 50% of NF patients develop malignancy

MRI

Diagnosis Neurofibromatosis type 1 (NF1) / Von Recklinghausen 

1.  Six or more café-au-lait spots (over 5mm in prepubertal individuals and over 15mm in postpubertal individuals)

2.  Two or more neurofibromas of any type or one plexiform neurofibroma

3.  Freckling in the axillary or inguinal region

4.  Optic glioma

5.  Two or more Lisch nodules (iris hamartomas)

6.  A distinctive osseous lesion such as sphenoid dysplasia or thinning of the long bone cortex with or without pseudarthrosis

7.  A first degree relative (parent, sibling, or offspring) with NF1 by the above criteria

Management

Localised

Surgical Indications

- pain

- nerve dysfunction

- rapid growth 

- suspicion of malignancy

Technique

- not easily separated from nerve

- excision usually involves partial resection of nerve

- if nerve small is sacrificed

- if nerve large and important need interposition graft

Plexiform 

Surgical Indications

- persistent symptoms / pain & numbness

- features of malignancy

Features of malignancy

- enlarging

- new or increasing pain

- perform biopsy

Technique

- excision difficult

- entering nerves usually sacrificed

- graft if needed

Liposarcoma

Definition

STS composed of malignant lipoblasts