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Epithelioid sarcoma of Enzinger.
1Royal Marsden Hospital, London SW3 6JJ, UK. cyril.fisher@rmh.nhs.uk
Advances in Anatomic Pathology
|June 17, 2006
Summary
Epithelioid sarcoma is a rare cancer primarily affecting young men, often in the extremities. It has a high recurrence and metastasis rate, requiring adequate surgical excision for better outcomes.
Area of Science:
- Oncology
- Pathology
- Surgical Oncology
Background:
- Epithelioid sarcoma, first described by Enzinger in 1970 and expanded in 1985, is a soft tissue sarcoma.
- It characteristically affects young adult males, with a predilection for the extremities, often involving subcutaneous tissue and tendon sheaths.
Observation:
- Tumors present as nodules with central necrosis, surrounded by bland polygonal cells with eosinophilic cytoplasm and peripheral spindling.
- Histological variants include fibromalike, angiomatoid, and aggressive proximal types with rhabdoid features.
- Immunohistochemically, epithelioid sarcomas express vimentin, cytokeratins, and epithelial membrane antigen; CD34 is positive in about half of cases. S100 protein, desmin, and FLI-1 are typically negative.
Findings:
- Ultrastructural analysis reveals both epithelial and mesenchymal features, including myofibroblastic differentiation.
- No specific genetic findings are consistently identified, though chromosomal abnormalities in the 22q region have been noted.
- Epithelioid sarcoma is distinct from synovial sarcoma and carcinoma, with a broad differential diagnosis including granuloma annulare, melanoma, and epithelioid vascular neoplasms.
Implications:
- Epithelioid sarcoma exhibits a high recurrence rate, emphasizing the importance of adequate surgical margins for treatment.
- Metastasis occurs in up to 40% of cases, commonly to regional lymph nodes, lungs, and scalp.
- Adverse prognostic factors include large tumor size, male sex, older age, necrosis, vascular invasion, rhabdoid morphology, and incomplete surgical resection.