Small cell carcinoma of the renal pelvis and ureter: Clinicopathologic and immunohistochemical features

Context.-Small cell carcinoma (SCC) of the renal pelvis and/or ureter is very rare, with only case reports published in the literature. Objective.-To describe the clinicopathologic and immunohistochemical findings in the largest series to date. Design.-A review of a regional cancer registry identified 10 cases diagnosed as SCC from 930 patients with renal pelvic and/or ureteral cancer from1971 to 1998. The original slides, demographics, treatment, and clinical outcome were reviewed. Representative sections were immunostained for AE1/AE3, cytokeratin 7, cytokeratin 20, CD56, synaptophysin, chromogranin, and thyroid transcription factor 1. Results.-Of the 10 cases, 5 were pure SCC, 2 were mixed (SCC and urothelial carcinoma), 2 were reclassified as poorly differentiated squamous carcinoma, and 1 was reclassified as urothelial carcinoma. The patients with SCC had an age range of 50 to 80 years (median, 72 years) with a female to male ratio of 2.5:1. All patients had non-organ confined disease. Five of 7 patients died of disease; 4 of those 5 had been clinically followed (median survival, 23 months) and 1 was diagnosed at autopsy. The SCC cases revealed positive staining of the SCC component as follows: AE1/AE3 (7 of 7), CD56 (7 of 7), synaptophysin (6 of 7), thyroid transcription factor 1 (5 of 7), chromogranin (4 of 7), and cytokeratin 7 (1 of 7). None were positive for cytokeratin 20 (0 of 7). Conclusions.-SCC of the renal pelvis/ureter is seen in a predominately female population in Sweden, is clinically aggressive, and has poor survival when presenting at an advanced stage in patients only treated by surgery. An immunostain panel serves as a useful adjunct in classifying these tumors.