Perirenal perivascular epithelioid cell tumor (PEComa) coexisting with other malignancies: a case report.

Perivascular epithelioid cell tumor (PEComa) is a very rare lesion and is described by the World Health Organization (WHO) as a mesenchymal tumor composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. In this report we describe PEComa with perirenal manifestation, which is exceedingly rare and to our best knowledge up to now worldwide only three cases have been described. Despite the reports that most PEComas are benign, this tumor met criteria for malignancy and coexisted with mucinous gallbladder cancer and nonresectable pancreatic head tumor. We concluded that despite the rarity of perirenal PEComas, in cases with an unusual epithelioid histological pattern the diagnosis of PEComa should also be taken into consideration on the basis of the immunohistochemical study.