Myeloma

Definition

 

Uncontrolled proliferation of single clone of plasma cells

 

Epidemiology

 

Most common malignant tumour of bone

 

Age 50-60

 

2-3 / 100 000

 

Pathology

 

Highly differentiated B lymphocytes

- associated with abnormality of protein synthesis

 

Usually bone marrow of entire skeleton involved

 

Two Forms

 

1.  Multiple Myeloma 95% 

 

2.  Plasmacytoma 5% 

- solitary bone or soft tissue lesion

- usually axial skeleton

- usually disseminates to MM in 5 - 10 years

 

Location

 

Always spine

 

Common in skull, ribs, sternum and pelvis

 

History

 

Bone pain / fatigue / fever / night sweats

 

Laboratory

 

Normocytic normochromic anaemia

 

Other signs bone marrow depression

- i.e. coagulation defects

- leukopenia

- thrombocytopenia

 

Elevated ESR > 100

 

Bence Jones Proteins in urine 50%

 

Serum & Urine Electrophoresis

- monoclonal antibody band

- most sensitive

 

Hypercalcaemia

Chronic Renal Failure

Elevated Serum Urate / Gout

 

Systemic Problems

 

Anaemia

Coagulation defects

Infection 2° immunological deficit

Hypercalcaemia

Amyloidosis 10%

CRF

Gout

 

X-ray

 

1.  Radiographic hallmark is punched out lytic lesions

- axial and appendical skeleton

- widely disseminated / soap bubble appearance

- no sclerotic reaction

 

Multiple Myeloma Pelvis0001Multiple Myeloma Pelvis0002Myeloma Humerus

 

2.  Diffuse osteopenia

- in 15% to 25% of patients, no discrete lysis occurs

- diffuse osteopenia and osteoporosis are the only skeletal manifestations

 

Multiple Myeloma Diffuse Osteopenia

 

3.  Vertebrae Plana

 

Spine Multiple Myeloma

 

4.  Pathological Fracture

 

5.  Pepper pot skull

 

Bone Scan

 

25% negative

- no malignant or reactive bone formation

 

Skeletal Survery

 

Required if negative bone scan

 

Xray

- skull / spine / humerus / femurs / pelvis / chest & ribs

 

Bone Marrow Biopsy

 

Definitive Diagnosis

 

Histology

 

Plasmocytoma Nephron GNU Free Documentation License Version 1.3

 

Sheets of plasma cells

- clock-faced eccentric nuclei

- perinuclear clear area

- increased rER on EM

- no background stroma

 

Cellular atypia not prognostic

 

May see amyloid

 

Management

 

Plasmacytoma 

 

Diagnostic criteria

 

Single osseous lesion confirmed on histology

Bone marrow aspirate from separate site

- < 10% plasmocytosis

No significant BJ in urine

No Ig abnormality in serum or urine

 

Clinical

 

Tend to be younger and have better prognosis

- usually long bone or vertebrae

- in spine commonly present with rapidly progressive paraplegia

- this is more common in plasmacytoma then multiple myeloma

 

NHx

 

70% of plasmacytoma will progress to multiple myeloma

 

Management

- requires biopsy

- resection of lesion if possible

- aggressive DXRT otherwise

 

Prognosis

 

30% cured by surgical en bloc excision and radiotherapy

 

Multiple Myeloma

 

Management

 

Chemotherapy

- corticosteroid

- alkylating agent - Melphalan / Cyclophosphamide

 

Radiotherapy

 

Surgical stabilisation of pathological fracture

 

Orthopedic Management

1. To confirm diagnosis - biopsy isolated lesion

2. To treat impending or actual pathological fracture

3. Rarely to excise solitary lesions

 

Prognosis

 

Multiple myeloma very aggressive with early death