Synchronous Type 1 Papillary Renal Cell Carcinoma in a Patient with Rectal Adenocarcinoma.

Synchronous colorectal cancer (CRC) and renal cell carcinoma (RCC) is relatively rare, particularly when the synchronous RCC is of papillary subtype, which is exceedingly rare. We report a case of a 63-year-old Caucasian man with synchronous CRC and type 1 papillary RCC. After the patient presented with three episodes of melena, colonoscopy followed by biopsy confirmed rectal adenocarcinoma. The computed tomographic imaging also showed an incidental mass of the upper pole of the left kidney suspicious for RCC. Once chemoradiation therapy was successfully completed, an ultra low anterior resection and partial nephrectomy were performed concurrently. Histological examination showed colorectal adenocarcinoma (ypT1 N0 Mx) and papillary RCC type I (pT1a Nx Mx). Although the exact pathogenesis of synchronous CRC and RCC is unknown, it has been suggested that almost all patients with this entity do not have Lynch syndrome. The majority of these patients usually present with CRC-related symptoms and then, during workup, are subsequently found to have an incidental renal mass that is most often diagnosed as clear cell subtype of RCC. To the best of our knowledge, this is only the second reported case of synchronous CRC and type 1 papillary RCC.