OBJECTIVETo study the pathologic features, diagnosis, differential diagnosis and biologic behavior of uterine perivascular epithelioid tumor.

METHODSFive cases of uterine perivascular epithelioid cell tumor were studied by light microscopy and immunohistochemistry. Follow-up information was reviewed.

RESULTSAll the five tumors were composed by clear or eosinophilic cells arranged in nests and cords, associated with abundant small vessels and hyalinization in the stroma. Immunohistochemically, the tumor cells demonstrated positive staining for melanocytic markers (HMB45 and/or Melan-A), desmin and smooth muscle actin. The staining for cytokeratin and CD10 was negative. All the patients followed for a certain period are still alive, with no evidence of disease recurrence.

CONCLUSIONSPerivascular epithelioid cell tumor is a rare mesenchymal tumor of uterus, with distinctive histologic and immunohistochemical features. It should be distinguished from clear cell carcinoma and epithelioid leiomyoma of uterus. Positivity for melanocytic markers (especially HMB45) plays an important role in the diagnosis of this tumor. In general, the tumor is categorized as benign, with uncertain malignant potential and malignant.