Background: The metastatic behavior of Renal Cell Carcinoma (RCC) is unpredictable and is known to metastasize synchronously and metachronously to various anatomic sites. However, metastasis to gallbladder is extremely rare with only 22 cases reported in the English literature from 1963 till present.
Case Report: We present the case of a 68 year-old male with a metachronous metastasis of RCC to the gallbladder. The patient underwent right nephrectomy in 2004 for T3B RCC and in 2007 during a routine radiological follow-up with ultrasound a hypervascular gallbladder mass was identified. Subsequently the patient underwent laparoscopic cholecystectomy which revealed an intraluminal polypoid mass. Microscopic examination showed clear-cell type cancerous cells, which were negative for cytokeratin 7 (CK7) and carcinoembryonic antigen (CEA) confirming the diagnosis of metastatic RCC.
Conclusions: Although metastasis of RCC to the gallbladder is extremely rare, it is a legitimate differential diagnosis in patients with known history of RCC. Preoperatively, dynamic contrast-enhanced CT can be helpful in differentiating from primary carcinoma of the gallbladder, as it would be hypervascular in the former. In selected cases, resection of the metastasis with cholecystectomy can improve long-term survival.

Keywords: renal cell carcinoma, Gallbladder, metastasis