Simultaneous double primary clear cell carcinomas of liver and kidney: a case report and review of literature.

Reported herein are simultaneous double primary clear cell carcinomas arising from liver and kidney. A 63-year-old man underwent a partial wedge nephrectomy of the right kidney in a surgical resection for hepatocellular carcinoma. Coincidently, on histology the tumors in liver and kidney were consisted of clear cancer cells, which arranged in haphazardly intermixed pattern without capsules. Immunohistochemically, the clear neoplastic cells in the liver were positive for HepPar-1, GPC3, and negative for nephrogenic markers; however, renal clear neoplastic cells were positive for CD10, RCC and Pax-8, but negative to liver-derived markers. These findings led to the diagnosis of simultaneous double primary clear cell carcinomas of kidney and liver. Multiple primary carcinomas of kidney and liver, especially both are primary clear cell carcinomas, are extremely rare neoplasms, only 1 case has been reported previously until now. To our knowledge, this is a report of multiple primary carcinomas arising from the liver and kidney and reminders us of differentiation diagnosis with carcinoma metastasis.