Malignant perivascular epithelioid cell tumor of the gallbladder: a case report and review of literature.

Perivascular epithelioid cell tumors are rare mesenchymal neoplasms composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. The perivascular epithelioid cell tumor family includes angiomyolipoma, clear cell sugar tumor of the lung, lymphangioleiomyomatosis, clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres, and rare clear cell tumors of other anatomic sites. Perivascular epithelioid cell tumors have been reported previously in various sites, but to our knowledge not in the gallbladder. We report here, for the first time, a malignant perivascular epithelioid cell tumor arising in the gallbladder.