[Clinicopathological study of 5 cases of proximal-type epithelioid sarcoma].

Objective: To investigate the clinicopathological characteristics, diagnosis and differential diagnoses of proximal-type epithelioid sarcoma (PES).

Methods: Five cases of PES were retrieved from pathology files. Clinical, pathologic and immunohistochemical features of the tumors were reviewed.

Results: One patient was female and 4 were male. Ages of the patients ranged from 19 to 46 years. The sites of the tumor involvement were vulvar (2 cases), hypogastric zone (1 case), anterosuperior iliac spine (1 case) and buttock (1 case). Clinically, the tumor masses were painless and progressive solitary nodules. Microscopically, the tumor cell growth was infiltrative in nature, nodular in appearance with degenerative and necrotic cells at the central areas. The tumors consisted of relatively uniform epithelioid cells with round or oval nuclei and eosinophilic cytoplasm. Immunohistochemically, the tumor cells were positive for vimentin (5/5), CK (4/5), EMA (4/5), beta-catenin (3/5), CD34 (3/5), and S-100 protein (1/5), but were negative for SMA, MyoD1, Desmin, HMB-45, CK7 and CK20.

Conclusion: Definitive diagnosis of PES relies on its histopathological characteristics in conjunction with appropriate immunohistochemical findings.