[833] Detailed Immunohistochemical Characterization in the Spectrum of Sex Cord Stromal Tumors (SCST) of the Testis Using Novel and Established Immunohistochemical (IHC) Markers: A Study of 41 Cases.

Loren P Herrera, Mitual Amin, John D Schwartz, Steven S Shen, Donna E Hansel, Gladell P Paner, Pheroz Tamboli, Komal Arora, Chandrakanth Annaiah, Rugvedita S Parakh, Mahul B Amin. Cedars-Sinai Medical Center, Los Angeles, CA; William Beaumont Hospital, Detroit, MI; The Methodist Hospital, Houston, TX; Cleveland Clinic, OH; University of Chicago, IL; MD Anderson Cancer Center, Houston, TX

Background: SCSTs of the testis are rare accounting for 4% of all testicular neoplasms. They present with a range of architectural & cytologic patterns & a spectrum of differentiation overlapping in their morphology with germ cell tumors, metastatic tumors & paratesticular neoplasms. Immunohistochemistry is a potentially useful diagnostic adjunct in these rare tumors with multiple patterns. SF1-steroidogenic factor 1, a nuclear transcription factor controlling steroidogenesis & development of the gonads, has recently shown to be of value in ovarian tumors – its expression in SCSTs of the testis is largely unknown.
Design: 41 SCSTs encompassing the range seen in the testis were evaluated using traditionally used (inhibin, melanA, calretinin, CD99, S100 and synaptophysin) & novel (SF1) IHC markers.
Results: IHC expression (in percentage) in different SCST subtypes is summarized in the table. Synaptophysin had the lowest positivity rate (17%) amongst all markers studied.

IHC expression (%) in different SCST subtypes

Type*	SF1	MelanA	Inhibin	Calretinin	WT1	S100	CD99
LCT (n=17)	94	94	94	94	5	11	41
SCT (n=6)	50	83	16	50	33	50	16
MSCST (n=5)	40	60	20	60	20	20	20
USCST (n=5)	100	80	40	80	50	60	40
GCT (n=4)	100	50	50	50	100	100	50
% (+)	71	73	63	74	31	33	40

* LCT – Leydig Cell Tumor, SCT – Sertoli Cell Tumor, MSCT – Mixed SCST, USCST – Unclassified SCST, GCT – Granulosa Cell Tumor. Data not shown for large cell SCST, signet ring cell SCST and adrenogenital syndrome tumors (n=4).


Conclusions: 1) SF1 is a sensitive marker for testicular SCST, however, its sensitivity is lower than reported for ovarian tumors (100%). 2) WT1 is less commonly expressed in testicular (31%) in contrast to ovarian (80-100%) SCSTs. 3) SF1, calretinin & melanA should constitute markers in a screening panel for testicular tumors in which SCST is in the differential diagnosis. 4) Depending on histological complexity, other useful SCST markers in the testis include inhibin and CD99.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 85, Tuesday Afternoon