Gallbladder Metastasis of Renal Cell Carcinoma: Report of Two Cases

We report two extremely rare cases of metastasis to the gallbladder from renal cell carcinoma. In both men, aged 63 and 80 years, a pedunculated polypoid gallbladder tumor was incidentally found 27 and 8 years after surgery for renal cell carcinoma, respectively. The tumors showed hypervascularity on diagnostic imaging. A histopathological examination showed no tumor cells in the gallbladder mucosa, but clear cell carcinoma was predominantly observed below the mucosal layer. Furthermore, based on various specific and immunohistochemical studies as well as the electron-microscopic findings, the patients were pathologically diagnosed to have gallbladder metastasis of renal cell carcinoma.