A case of perivascular epithelioid cell tumor (PEComa) arising in the colon

Perivascular epithelioid cell tumor (PEComa) is a rare family of related mesenchymal neoplasms that include angiomyolipoma, lymphangiomyomatosis and clear cell 'sugar' tumor of the lung. Although this type of tumor has been described in the literature in organs such as kidney, lung, uterus and urinary bladder, there are few reports of gastrointestinal tract-related tumor. We report here on a case of PEComa arising in the transverse colon. This occurred in a 41-year-old male who had no history of tuberous sclerosis complex. Histopathologically, the tumor consisted of nests or sheets of epithelioid cells with eosinophilic cytoplasm. The tumor cells were positive for HMB-45, vimentin and caldesmon, but they were negative for S-100 protein, cytokeratin and CD117, according to immunohistochemical staining. Careful follow up is warranted because the biological behavior of PEComa has not yet been documented. We present here a case of colonic PEComa that was confirmed by immunohistochemical staining and the histopathologic findings, and we include a review of the literature.