Malignant Soft Tissue Tumours

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