[1165] Juvenile Granulosa Cell Tumors: Immunoreactivity for CD99 and Fli-1 and EWSR1 Translocation Status. A Study of Eleven Cases

Elke A Jarboe, Lester J Layfield, Michelle L Wallander, Sheryl R Tripp. University of Utah School of Medicine, Salt Lake City, UT; ARUP Laboratories, Salt Lake City, UT

Background: The accurate diagnosis of a juvenile granulosa cell tumor (JGCT) can be challenging, as these neoplasms often exhibit morphologic features which overlap other ovarian neoplasms. Additionally, the immunohistochemical profile exhibited by JGCTs is fairly non-specific and may include reactivity with CD99. Recently, we noted that JGCTs can show strong immunohistochemical expression of Fli-1, a transcription factor expressed by Ewing's sarcoma, a neoplasm which is occasionally in the differential diagnosis with JGCT. We evaluated a series of JGCTs, to determine whether Fli-1 is commonly expressed by these tumors, and whether or not they demonstrate chromosomal rearrangements in EWSR1.
Design: Cases diagnosed as JGCT (n=11) were immunohistochemically evaluated for the expression of Fli-1 and CD99. Fluorescence in situ hybridization (FISH) was performed on all cases to look for chromosomal rearrangements involving EWSR1.
Results: All eleven of our cases exhibited positive immunohistochemical staining for Fli-1 and CD99. None of these cases demonstrated a rearrangement in EWSR1 by FISH.
Conclusions: In cases of JGCT which cannot be reliably distinguished from Ewing's sarcoma based on morphology and immunohistochemistry alone, FISH testing for EWSR1 rearrangements can be a useful diagnostic adjunct for their separation.
Category: Gynecologic & Obstetrics

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 199, Tuesday Morning

 

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