Rhabdomyosarcoma
Definition
Malignant tumour of striated muscle
Juvenile variety arises from mesenchyme
Epidemiology
Most common malignant ST Tumour in children (< 15 years)
Malignant tumour of striated muscle
Juvenile variety arises from mesenchyme
Most common malignant ST Tumour in children (< 15 years)
Schwannoma
- benign tumour of nerve sheath
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
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
Most common in young females
- peak age 15-30
- F:M = 3:1
Most common tumour in hand (2/3)
Unclear
Uncommon
- 4% OS
Females more common
- similar to GCT
Less aggressive locally
- less metastasis
- size / location & duration of symptoms don't correlate with outcome
Arise from cortex of bone / periosteum
- parosteal
- periosteal
- high grade juxtacortical
Uncontrolled proliferation of single clone of plasma cells
Most common malignant tumour of bone
Age 50-60
2-3 / 100 000
Highly differentiated B lymphocytes
- associated with abnormality of protein synthesis
Usually bone marrow of entire skeleton involved
Malignant cartilage producing tumour
20% of primary bone tumours
3rd most common
- 1 in 500 000
Relatively non-aggressive / usually Grade I
Average age 40
Male > Females
Arises de novo
Metaphyseal Enchondroma
Arise from the metaphyseal cortex of long bones
- most common in the proximal humerus
Difficult to DDx from Chondrosarcoma
Masses of cartilage nestling in a shallow crater in the periphery of the cortex
Don't ossify
- remain as immature cartilage
Non Ossifying Fibroma
A hamartomatous defect in the metaphyseal cortex of skeletally-immature adolescents
Fibrous cortical defect
- < 2cm in diameter
Non ossifying fibromas
- > 2cm
Benign lesion with a wide spectrum of behavior characterized by stromal cells and giant cells
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
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
E - H - L