Collecting duct carcinoma of the kidney presenting uncommon findings

Abstract

We present a case of collecting duct carcinoma (CDC) of the kidney exhibiting uncommon radiologic findings. A 67-year-old man had a history of hepatic resection for hepatocellular carcinomas. Follow-up CT revealed a left renal mass that presented an exophytic appearance with distortion of the renal contour. Since malignancy was suspected, the patient underwent a left radical nephrectomy with partial adrenalectomy and para-aortic lymph nodes dissection. Histologically, the majority of the tumor showed a tubular structure, and the rest was a solid area resembling transitional cell carcinoma (TCC). A diagnosis of CDC was made. In previous reports, common radiologic findings of CDC have been a medullary location and infiltrative appearance. Therefore, the outer contour of the affected kidney is usually maintained when the mass is relatively small. However, the present case did not show these common findings. In conclusion, the radiologic findings of CDC may be various and we should consider this tumor in the differential diagnosis of renal tumors.