[890] Leydig Cell Tumors of the Testis, a Clinicopathological Series with Malignant Histological Features

F Tavora, JH Barton, I Sesterhenn. Armed Forces Institute of Pathology, Washington, DC

Background: Malignant Leydig cell tumors of the testis are uncommon. To date, only small series have been reported.
Design: From a database of 724 Leydig cell tumors, 84 Leydig cell tumors from the Testicular Tumor Registry of the AFIP from 1979 to 1998 were selected based on the presence of one or more of the following features: cellular pleomorphism, tumor necrosis, vascular invasion, increased number of mitotic figures or atypical mitotic figures. Unclassifiable gonadal stromal tumors and cases with Sertoliform differentiation were excluded. Mitotic figures, necrosis, degree of atypia, and extension to paratesticular tissue were correlated with aggressive behavior (presence of vascular invasion or metastatic disease at the time of diagnosis). Unusual histologic features were recorded.
Results: The mean age of the patients was 55 years (range 19-94). Tumor sizes ranged from 1.1 to 14cm (mean 4.7). The tumors were characterized most often by sheets of polygonal cells with abundant cytoplasm and central nuclei. Degree of pleomorphism was coded as mild (23.8%), moderate (32.1%) and severe (44%). Unusual features included signet-ring cell changes (2%), foamy cells (%), adipose metaplasia (10%), calcification (3%), vacuolated cells (12%), myxoid changes (12%) and areas of spindling (21%). Mitotic figure counts ranged from 0 to 24/10HPF (mean 6.4). 65 cases (77%) had tumor necrosis, ranging from 5 to 80% (mean 22.9%). Tumors with metastasis at diagnosis (9, 10%) or vascular invasion (20, 23%) occurred in older patients (p=0.004), were larger (p=0.002) and had a higher mitotic count (p=0.04) compared to others. Percent necrosis, extension into paratesticular tissue, spindle cell change, presence of atypical mitoses, circumscription, fibrous bands and degree and extent of anaplasia were not significantly different between aggressive tumors at presentation and the others. Survival data from 21 patients (25%) revealed mean overall survival of 73 months (range 0-300 months).
Conclusions: Mitotic counts, tumor size and patient age correlate with presence of metastic disease at diagnosis or presence of vascular invasion and suggest aggressive behavior in a subset of Leydig cell tumors with malignant histologic features.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 11:45 AM

Platform Session: Section A, Monday Morning