Synchronous diagnosis of signet ring cell colon carcinoma and transitional carcinoma of the left distal ureter.

The presence of synchronous multiple primary carcinomas, although recognized, remains very uncommon. Their etiopathogeny is unclear. The wide spread of imaging techniques currently facilitates diagnosis of simultaneous tumors. We present the rare case of a signet ring cell colon carcinoma coexisting with a transitional cell carcinoma (TCC) of the ureter, which debuted with symptoms of intestinal obstruction in a 75-year-old male patient, with no prior relevant history. Computed tomography showed signs of a tumor mass on the transverse colon, as well as left hydronephrosis with a tumor in the lower third of the ureter, which prompted for immediate emergency surgery. After the appropriate surgical maneuvers, tissue collected from both tumors underwent usual histological preparation and Hematoxylin-Eosin staining, as well as multiple immunostaining with a complex panel of markers. The patient had a favorable postoperative course and during a six-month follow-up, we did not detect any signs of illness.