Pecoma of Uterus with Unique Morphological and Immunohistochemical Features

Perivascular epitheloid cells (PECs) are present in a group of tumor called PEComas including angiomyolipoma (AML), clear cell sugar tumor (CCST) of the lung and extrapulmonary sites, lymphangioleiomyomatosis, clear cell myomelanocytictumor of the falciform ligament/ligamentumteres and rare clear cell tumor of other anatomic sites. PEComas have distinct, morphologic and immunohistochemical characteristics, including perivascular epitheloid cells with clear to granular cytoplasm, a round to oval, centrally located nucleus, and an inconsipicuous nucleolus. PEComas also express melanocytic and myogenic markers like HMB-45 and smooth muscle actin. We report a case of uterine PEComa. The patient presented with abnormal uterine bleeding and grossly mass in uterus. Histopathologically, the tumor was composed of thick blood vessels and perivascular epitheloid cells. The neoplastic cells were immunoreactive for HMB-45 antigen, Desmin, SMA and CD10-ve, Ki-67 labelling index was less than1 %. Uterine Pecoma should be considered a tumor of uncertain malignant potential and long term follow up required.