Renal cell carcinoma with direct colonic invasion.

Renal cell carcinoma (RCC) is a fairly uncommon malignancy, comprising only 3% of malignancies in adults [1]. Symptoms related to gastrointestinal involvement of this tumor rarely present, although up to 4% of patients with RCC have small-bowel metastases. Direct colonic invasion by RCC is extremely rare due to the retroperitoneal location of the kidneys and mesocolon. A thorough search of the English medical literature revealed only three reported cases of RCC with direct invasion into the colon [2–4]. Here, we present another case with a brief literature review. A 53-year-old man presented with intermittent hematochezia and left flank pain. A computed tomographic (CT) scan of the abdomen revealed a 7-cm, left renal mass extending into the descending colon, with suspected fistulous communication (●" Fig.1). Colonoscopy revealed significant luminal narrowing in the proximal descending colon with multiple, friablemass lesions (●" Fig.2 and●" Video 1). Biopsy specimens showed a poorly differentiated carcinoma, lacking both glandular and squamous features. Immunohistochemical analysis revealed tumor cells with marked reactivity for cytokeratin AE1/AE3 and vimentin stains. Scattered S100-positive cells were interspersed among the tumor cells. Fig.1 Computed tomography (CT) image of a gigantic left kidney mass (arrow) invading the descending colon in a 53-year-old man with intermittent hematochezia and left flank pain. No pneumoperitoneum was noted.