Concurrent renal tubulocystic carcinoma with gastrointestinal stromal tumor: a case report

Reported herein is a coexistence of renal cell carcinoma in a gastrointestinal stromal tumor (GIST) patient. A 77-year-old male suffered from renal tubulocystic carcinoma in the left kidney and spindle cell gastrointestinal stromal tumors. Immunohistochemically, the renal cancer cells showed expression of Vimentin, Ckpan, CK18, CK19, CD10, P504S and Pax-8, focal positive of CK7, 34βE12, Ksp-cad and EMA, but negative for CK20, CA9, CD117, P63, CD15 and Villin. The gastric tumor indicated expression of CD117, CD34, DOG-1 and Nestin, while negative for CKpan, EMA, SMA, Caldesmon and S-100 and Ki67 index was less than 1%. About 14%~43% of GISTs were observed to develop additional primary malignancies preoperatively or postoperatively. To our knowledge, this is the first case of coexistence of tubular cystic carcinoma and GIST.