[832] Small Cell Carcinoma of the Renal Pelvis and Ureter: Clinicopathologic and Immunohistochemical Features

R Miller, SM Lele, S Holmang, S Johansson. University of Nebraska Medical Center, Omaha, NE; Sahlgrenska University Hospital, Goteborg, Sweden

Background: Small cell carcinoma (SCC) arising in the renal pelvis and ureter is rare, with only case reports published in the literature. These tumors may be difficult to identify especially when mixed with a high-grade urothelial carcinoma. Further, the immunohistochemical staining pattern of these tumors arising in the renal pelvis and ureter has not been well characterized in the literature. We report the clinicopathologic and immunohistochemical findings in the largest series of such cases to date.
Design: A review of the regional cancer registry identified 10 cases diagnosed as SCC from 858 patients with renal pelvic or ureteral cancer from 1971 to 1998. The original slides, demographic data, treatment, and clinical outcome were reviewed. The original blocks were recut and stained with hematoxylin and eosin and immunostained for AE1/AE3, CK7, CK20, CD56, synaptophysin, chromogranin and TTF1 using commercially available antibodies. The cases were reclassified using previously published morphologic criteria and the immunostaining pattern of each histologic subtype was assessed semi-quantitatively.
Results: On review of the 10 cases, 5 were pure SCC and 2 had a mixed pattern [urothelial carcinoma (UC) and SCC]. The others were reclassified based on histologic features as poorly differentiated squamous carcinoma (2) and high-grade UC (1) . The 7 SCCs (pure and mixed) had an age range of 50 to 80 years (median: 67 years) with a female:male ratio of 2.5:1. The pathologic stages were IV (6/7) and III (1/7). None of the cases received neoadjuvant therapy. Of the 7 cases, 6 died of disease (median survival: 8 months) and one patient died of unrelated causes. The SCC cases (pure and SCC foci in mixed tumors) revealed positive staining as follows: AE1/AE3 (7/7), CK7 (1/7), CD56 (7/7), synaptophysin (6/7), chromogranin (4/7) and TTF-1 (5/7). Negative staining was noted for CK20 (7/7). In the mixed tumors, foci of non-SCC were positive for CD56 (2/2), focally and weakly positive for chromogranin (1/2), and negative for synaptophysin (0/2) and TTF-1 (0/2). The pure non-SCC were negative for all neuroendocrine markers.
Conclusions: SCC of the renal pelvis and ureter usually presents at an advanced stage and is clinically aggressive with poor survival. It appears to be twice as common in females than in males. Immunostaining, especially for CD56, synaptophysin, TTF-1, CK7 and CK20, may help in distinguishing these tumors from their mimics.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 131, Monday Morning