Epidemiology
Most common malignant tumour
- malignant melanoma
Most common sarcoma
- synovial sarcoma 50%
- consider it for every foot lump
- most in dorsum and hindfoot
Foot and ankle considered single compartment
- Enneking staging
- unless tumour confined to singe ray
1. Synovial Sarcoma
Consider it for every foot lump
Diagnosis often delayed
- varied presentation
- slow growing firm fixed mass
- indolent course
- small latent mass with period of rapid growth
- rapidly growing mass
- painful (even before mass) or painless lump
Peak incidence 20-50
Spread via lymphatics (rare for sarcoma)
X-ray
- soft tissue mass (+/- Ca++)
MRI
- aggressive on appearance
Prognosis
- size can predict outcome
Treatment
- wide / radical excision +/- DXRT
- ? role of chemotherapy
2. Malignant melanoma
Common in the foot
- often in junctional naevi
Treatment
- wide excision
- depth of lesion most important prognostically
- assess lymph nodes
3. Subungal melanoma
Less aggressive than other MM
- present with loss of the nail
DDx
- haematoma
- mark nail with knife
- return 2 weeks later
- if melanoma the pigment will be in same position and the mark on the nail will be distal
Treatment
- toe amputation
- assess lymph nodes
4. Clear cell sarcoma
Highly malignant
- common in foot and ankle (43%)
- usually 2nd/3rd decade
- wide excision +/- chemotherapy
5. Epithelioid sarcoma
Innocuous nodule on the dorsum of the foot in young adults
- wide / radical excision
- lymphatic & haematogenous spread
6. Hemangioendothelioma
Vascular tumor in bones or soft tissue
- any age
- multiple on same extremity
- wide excison +/- DXRT
- long follow up for all
- difficult to predict which will behave aggressively
7. Acral Myxoinflammatory Fibroblastic Sarcoma
DDx ganglion, GCTTS, tenosynovitis
- low grade
- don't metastasise but can recur locally
- marginal excision
8. Fibrosarcoma
Prognosis depends on histological grade
- wide / radical excision
- in childhood need less aggressive treatment