[791] Comparative Utility of Novel Nuclear Markers Steroidogenic Factor (SF-1) and Forkhead Box L2 (FOXL2) in the Diagnosis of Sex Cord Stromal Tumors (SCST) of the Testis

Manju Aron, Allen M Gown, Bonnie L Balzer, Mitual Amin, Steven Shen, Donna E Hansel, Pheroz Tamboli, Gladell Paner, Daniel J Luthringer, Sambit K Mohanty, Loren P Herrera, Mahul B Amin. Cedars-Sinai Medical Center, Los Angeles; Phenopath Laboratories, Seattle; William Beaumont Hospital, Detroit; The Methodist Hospital, Houston; Cleveland Clinic, Cleveland; M.D. Anderson Cancer Center, Houston; University of Chicago, Chicago

Background: SCSTs of the testis may demonstrate a range of cytoarchitectural patterns that can overlap with other tumors including germ cell tumors, metastatic tumors and paratesticular neoplasms. Immunohistochemistry plays an important part in the diagnosis of SCST of the testis, and although several markers have been identified, many available markers have overlap in staining reaction with differential diagnostic considerations. SF-1 (adrenal 4-binding protein; Ad4BP) is a nuclear transcription factor involved in gonadal and adrenal development. FOXL2 is a transcription factor required for ovarian differentiation in mammals. Both SF-1 and FOXL2 have been recently shown to be of value in ovarian tumors, however the expression of these markers and their potential utility in SCST of the testis is largely unknown.
Design: A total of 24 cases of SCST of the testes comprising of Leydig cell tumor (n=9), Sertoli cell tumor (n=3), large cell calcifying Sertoli cell tumor (LCCSCT) (n=3), unclassified and mixed SCST (n=6), and 1 case each of testicular tumor of androgenital syndrome (TTAG), signet ring stromal tumor and granulosa cell tumor were included in the study. All the cases were stained by SF-1 and FOXL2. The extent and intensity of nuclear staining was graded both qualitatively and semiquantitatively.
Results: The results of the study are outlined in the table.

Diagnosis	SF-1 percentage positivity	FOXL2 percentage positivity
Leydig cell tumor	78	11
Sertoli cell tumor	33	67
LCCSCT	33	0
Signet ring stromal tumor	100	100
Granulosa cell tumor	0	100
TTAG	100	0
Unclassified/mixed SCST	83	33
Total	66	29

Conclusions: 1) SF1 (66%) is a more sensitive marker for SCST of the testis, compared to FOXL2 (29%), however, its sensitivity is lower than that reported for ovarian tumors (100%). 2) FOXL2 is more sensitive for Sertoli cell tumors (67%) compared to Leydig cell tumors (11%), however its staining is lower than ovarian SCST (80%). 3) In 58% of SCST, either SF1 or FOXL2, but not both markers, were positive. 4) Depending on the differential diagnostic consideration and complexity of the case, SF1 or FOXL2, calretinin, melan-A and inhibin should constitute a comprehensive panel for SCST of the testis.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 1:00 PM

Poster Session II # 136, Monday Afternoon