Epithelioid sarcoma: the clinicopathological complexities of this rare soft tissue sarcoma.

BACKGROUND: Epithelioid sarcoma is a rare high grade soft tissue sarcoma with a known propensity for locoregional recurrence. The literature is limited on other characteristics such as frequency of multifocal disease at presentation, the relationship of presenting size of the primary lesion to prognosis, and the ability of current staging systems to predict prognosis.
METHODS: Review of the Royal Marsden National Health Service Trust (RMH) experience of 37 cases over 21 years.
RESULTS: The mean age was 29 years, with male predominance (2.7:1), and distal limb locations were most common (56%). Five patients presented with multifocal local disease. Median follow-up was 88 months in the 19 patients still alive. The 5- and 10-year actuarial overall survival was 70% and 42%, respectively. Tumors deep to the investing fascia had a worse prognosis than superficial tumors. Regional metastasis events were also associated with significantly worse overall survival. Local recurrence, size of 5 cm or larger, and regional metastasis events were predictive of worse distant metastasis-free survival. Tumor size (<5 cm vs. > or =5 cm), local recurrence events, sex, and site were not significant predictors of survival. The American Joint Committee on Cancer/International Union Against Cancer staging systems and the recently proposed RMH staging system of the Royal Marsden National Health Service Trust provided poor differentiation of prognosis in epithelioid sarcoma. The 5-year actuarial local recurrence rate was 35%. The 5-year actuarial regional nodal metastasis rate was 23%. The actuarial 5-year distant metastasis rate was 40%, with pleuropulmonary metastases the most common site of metastatic disease, and 35% of pleuropulmonary metastases presented with pleural effusion. Median post-distant metastasis survival was 8 months.
CONCLUSIONS: Epithelioid sarcoma has unusual clinical behavior compared with other high grade soft tissue sarcoma. It has a propensity for multifocal disease at presentation, local recurrence, regional metastasis, and particularly poor prognosis after regional or distant metastatic disease. Size and stage according to the American Joint Committee on Cancer/International Union Against Cancer are unreliable predictors of prognosis.