診断に苦慮した腎細胞癌大腸転移の一例

抄録

A male aged in his 60s was admitted to our hospital with abdominal pain, fever and vomiting. He revealed a history of bilateral nephrectomy for renal cell carcinoma (RCC) and was undergoing dialysis. Computed tomography (CT) showed no recurrence of RCC and distant metastasis; however, multiple colonic diverticula were observed in the left-sided colon. Colonoscopy (CS) revealed a longitudinal nodular mucosal elevated lesion (not a diverticulum) in the descending colon, and following a confirmatory biopsy, the lesion was diagnosed as inflammatory regenerative and granulation tissue. Follow-up CT and CS were performed 5 months later and showed severe colonic stenosis secondary to a submucosal tumor-like lesion. Biopsy examination of the stenotic lesion revealed spindle-shaped atypical cells, which on immunohistochemical examination stained positive for CD10, CA9, and PAX8 stains leading to a diagnosis of colonic metastasis of RCC. Left hemicolectomy was performed, and histopathological examination of the resected specimen showed sarcomatoid RCC, similar to the findings at the time of the left nephrectomy performed 2 years earlier.