Clinicopathologic features of epithelioid sarcoma: report of seventeen cases and review of literature.

Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor, which is characterized by nodular aggregates of epithelioid cells and immunoreactivity of cytokeratin (CK) as well as epithelial membrane antigen (EMA) and often with CD34. It can be divided into proximal and distal subtypes. Classic ES has a microscopic nodular appearance that is composed of large polygonal epithelioid cells combined with central necrosis, and presents as a subcutaneous or deep dermal mass in the distal extremities of young adults. The proximal variant preferentially occurs in proximal limbs and limb girdles and the midline of the trunk, and is composed of more atypical cells with variable rhabdoid morphology. In this study we investigated the clinicopathologic features of 17 patients diagnosed with ES. In addition, we reviewed relevant literature and discussed some diagnostic and differential diagnostic points of this disease.