location

Periosteal Osteosarcoma

 

Definition

 

Intermediate grade chondroblastic osteosarcoma arising from surface of long bones

 

Epidemiology

 

Extremely rare

- 1% of all osteosarcomas

- 25% of surface osteosarcomas

 

Age 15-25

 

Location

 

Typically anterior proximal tibia

- diaphysis of major long bones

- humerus

 

Pathology

 

Chordoma

Definition

 

Primary malignancy arising from remnants of the notochord

 

Epidemiology

 

Rare malignant tumour

 

Middle-aged adults (50-70)

 

M>F

 

Location

 

In midline in axial skeleton

 

Base of skull 35%

 

Vertebrae 15%

- especially cervical

 

Sacrum 50%

 

Synovial Sarcoma

Epidemiology

 

4th most common STS

- 10-35% of STS

 

Peak age 3rd-4th decade

- rare in children

 

Pathology

 

Cellular characteristics suggest tumour arises from primitive synovial cells

- rarely actually occurs within joint

 

Characteristic

 

Occasionally metastasis to lymph nodes (5-7%) 

- like Epitheloid Sarcoma 

Non-Ossifying Fibroma

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

 

Non Ossifying Fibroma

 

Aetiology

 

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