[1136] CYP11A1, STAR and SULT1E1 Expression in Ovarian Leydig Cell Tumors.

Jamie L Steinmetz, Rebecca Buell-Gutbrod, Anthony Montag, Katja Gwin. University of Chicago Medical Center, IL

Background: Leydig cell tumor (LCT) of the ovary is a rare sex cord-stromal tumor composed of cells recapitulating normal Leydig cell development, being composed of cells with abundant granular eosinophilic cytoplasm, distinct cell borders and, in 50% of cases, pathognomonic Reinke crystals. LCTs can have overlapping histologic features with granulosa cell tumors, clear cell carcinomas, vascular tumors or lipid-rich Sertoli-Leydig cell tumors (SLCT). Although vimentin and inhibin are commonly used as markers for LCTs, these are non-specific; there are currently no specific and sensitive IHC markers for ovarian LCTs. Based on the steroidogenesis pathway, we identified three potential new LC IHC markers: CYP11A1, STAR and SULT1E1. The aim of our study was to further characterize the expression of these enzymes in ovarian LCTs.
Design: Paraffin embedded material from 3 LCTs was examined by IHC for the expression and localization of CYP11A1, STAR and SULT1E1. Normal testicular tissue, 7 LCT of the testis and 10 Sertoli Leydig cell tumors (SLCT) were used as controls. Staining intensity was scored on a scale of 0-3 with 0 being no staining and 3 being the most intense staining.
Results: All 3 LCTs revealed cytoplasmic staining for SULT1E1 (3=33%, 2=67%, 1=0%, 0=0%), CYP11A1 (3= 67%, 2=0%, 1=33%, 0=0%), and STAR (3 =0%, 2=67%, 1=33%, 0=0%). In the control group, Leydig cells in both testicular LCTs and normal testis revealed cytoplasmic staining for CYP11A1, STAR and SULT1E1. Sertoli cells and germ cells in normal testis and Sertoli cells in SLCT were negative for all three markers. The Leydig cell component of SLCT expressed all three markers.
Conclusions: Our findings support that the three markers CYP11A1, STAR and SULT1E1, components of the biosynthetic pathway of testosterone production, are useful to identify ovarian LCTs and are more specific than the currently used markers inhibin and vimentin. As none of the new markers are expressed in either Sertoli cells or germ cells, this panel can help to distinguish LCTs from other sex cord-stromal tumors as well as from germ cell tumors.
Category: Gynecologic & Obstetrics

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 124, Tuesday Afternoon


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