[857] Immunohitochemical Study of Multilocular Cystic Renal Cell Carcinoma
BM Purgina, TA Flood, KT Mai, B Nguyen, EC Marginean. University of Ottawa, Ottawa, ON, Canada; Ottawa, ON
Background: Multilocular cystic clear cell renal cell carcinoma (MCCRCC) is a distinct subtype of renal cell carcinoma (RCC). The immunohistchemical properties of MCCRCC have not been studied.
Design: 21 MCCRCC were retrieved from the files at our institution. All cases were submitted for immunohistochemical studies. Five alveolar clear cell RCC (CRCC) measuring less than 2 cm in diameter and two cystic nephromas (CN) with focal clear epithelial cells were used as control.
Results: MCRCC were associated with female:male ratio of 1:4. The patient ages or tumor sizes ranged from 45 to 75 years (64
8) and 2.5 8 (42.5). Immunostaining for CK7 showed extensive reactivity in 3 tumors (group 1), focal immunostaining in 7 tumors (group 2) and negative in 11 cases (group 3). In group 1, the MCCRCC were predominantly cystic, with minor solid component. The tumor had focal areas of chromophil cells and displayed negative reactivity for RCC and weak reactivity for CD10. The intercystic septae were relatively cellular and showed positive reactivity for PR in a large number of cells. Group 3 showed large solid areas of clear cells. The tumor cells showed positive reactivity for RCC and CD10, and the intercystic stroma was sclerotic and showed negative reactivity for PR. Group 2 had intermediate histologic and immunhistopathological features of the other two groups. Immunostaining for CRCC and CN showed CK7-RCC+/CD10+/PR- and CK7+/focal CD+/focal RCC+/PR+ for CRCC and CN as previously described in literature. Focal areas with clear cells in CN showed weak CK7+.
Conclusions: Some MCRCC contained areas simulating CN. We propose that there is at least a subset of MCRCC that develop from CN. The difference in gender ratio between MCRCC and CN may be due to the fact that CRCC tend to develop more often in CN in male patients.
Category: Genitourinary (including renal tumors)
Tuesday, March 10, 2009 9:30 AM
Poster Session III # 79, Tuesday Morning