Epithelioid sarcoma is a relatively new concept (1970) and it generally occurs in teenagers and young adults, especially men.
Aetiology and Pathogenesis
No known aetiology.
The tumour often arises in the extremities over the flexor surface of the hand. Tumours can also from the other parts of the limbs but it is rare to encounter a primary tumour in the trunk. Distant metastases are common (40%+) and local recurrences are the norm (50%).
Tumour/Normal Tissue Features
The central part of the tumour is frequently necrotic. The remaining tissue is usually white. The tumour often forms superficial nodules.
The tumour contains two cell populations: polygonal to oval epithelioid cells and more typical spindle cells. The cytoplasm is eosinophilic and cell borders are indistinct.
Tumour cell stain positively for vimentin for epithelial membrane antigen.
There are no specific genetic abnormalities.