[947] Morphological and Immunohistochemical Findings in a Large Series of Sex Cord-Stromal Tumors

Sarah Lam Shang Leen, Daniel M Berney. Bartshealth NHS Trust, London, United Kingdom

Background: Sex cord stromal tumours (SCST) of the testis are rare tumors, in which the morphology, immunochemistry (IHC) and criteria for malignancy are not well established as behaviour can be unpredictable.
Design: The archives of Bartshealth NHS trust were searched for both primary and consult cases of SCSTs. Cases were reviewed and the following information collected: patient demographics, tumour size, mitotic count, necrosis, and lymphovascular invasion (LVI) and where available, IHC including inhibin, calretinin, S100, CD99, and Ki-67.
Results: There were 73 SCSTs (referral cases =50) including 29 Leydig cell tumors (LCTs) (24 benign, 5 malignant), 27 Sertoli cell tumors (SCTs) (19 benign, 8 malignant), 2 granulosa cell tumors (GCT), and 15 mixed SCSTs (13 benign, 2 malignant). The age range for the LCTs was 32 to 93y (mean 48.4y), SCTs 18 to 71y (mean 44.5y), and mixed SCSTs and GCTs 5 months to 74 y (mean 49.5y). The designated malignant tumors had a larger mean size than their benign counterparts: LCTs, benign =14.4mm, malignant = 42.8mm; SCTs, benign = 9.7mm, malignant =48.1mm; mixed SCSTs and GCTs, benign 24.7mm, malignant 38.5mm. In the designated benign tumors, necrosis was seen in a single case (1/58) no LVI was seen, average mitotic count was 1/10HPF and Ki67 (performed in 21/58 cases) ranged from 1-20%. In the designated malignant tumors there was necrosis in 50% (7/13), LVI in 15% (2/12), mean mitotic count 7.8/10HPF, and Ki67 (performed in 7/14 cases) ranged from 10-50%. IHC had not been performed on all of the tumors. The SCTs showed inhibin staining in 45% (11/25), calretinin staining in 45% (9/21), S100 staining in 55% (9/16), and CD99 staining in 70% (12/17). The mixed SCSTs and GCTs showed: inhibin staining in 75% (13/17), calretinin staining in 75% (11/15), S100 staining in 40% (6/15), and CD99 staining in 55% (6/11). The LCTs showed inhibin staining in 100% (12/12), calretinin staining in 90% (8/9) and S100 staining in 50% (3/6). Follow-up time is variable, but at present, 5 men diagnosed with malignancy have died from metastatic disease. There is no report of a benign tumor metastasizing.
Conclusions: This large series of SCSTs emphasizes the extreme variability of these rare neoplasms. Criteria most often helpful in designating malignancy incuded tumor size and necrosis. LVI was less helpful. Mitotic count and Ki-67 scores were variable, but were higher in those designated malignant. IHC shows that staining patterns in SCTs and mixed tumors are much more variable than LCTs. A large panel is necessary as tumors may be negative with more usual markers such as inhibin.
Category: Genitourinary (including renal tumors)

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 139, Monday Morning

 

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