0022-5347/99/1613-1024$03.00/0 THE JOLTWAL OF UROLOCY Copyright Q 1999 by Amiucm Ummrc~L A s s o c u n O N , INC.

Vol. 161, 1024-1052, March 1999 Printed in U.S.A.

ABSTRACTS DIAGNOSTIC UROLOGY AND TESTIS CANCER

Germ Cell Tumors of the Mediastinum and Testis: A Comparative Immunohistochemical Study of 120 cases

S. SUSTER, C. A. MOW, H. DOMINGUEZ-WWN AND P. QUEVEDO-BLANCO, Arkadi M. Rywlin Department o f Pathology and Laboratory Medicine, Mount Sinai Medical Center and University of Miami School of Medicine, Miami, Florida, Department of Pulmonary and Mediastinal Pathology, Armed Forces Institute of Pathology, Washington, D. C. and National Cancer Institute, Mexico City, Mexico

Hum. Path., 2 9 737-742, 1998 An immunohistochemical study was performed in 120 cases of mediastinal and testicular germ cell

tumors from archival, paraffin-embedded material to compare the patterns of expression between the two groups with a panel of markers, including broad-spectrum keratin, CAM 5.2 low-molecular-weight cytoker- atin, placental-like alkaline phosphatase (PLAP), alpha-fetoprotein (AFP), human 0-chorionic gonadotropin (hCG), vimentin, and CD30 (Ki-1 antigen). Significant differences were observed between mediastinal and testicular seminomas: mediastinal seminomas showed strong dot-like para-nuclear positivity of the tumor cells with antibodies to CAM 5.2 low-molecular-weight keratin in 80% of cases (32 of 401, as compared with only 20% positivity (5 of 24) in testicular seminomas; placental alkaline phosphatase (PLAP) was also found to be less commonly expressed in testicular seminomas (12 of 24) than in mediastinal seminomas (37 of 40); a similar pattern of expression was also observed for vimentin, which was present in scattered tumor cells in a higher proportion of mediastinal seminomas (28 of 40) than in testicular seminomas (11 of 24). The staining pattern and distribution of these markers did not show significant differences between the two groups for the various other tumor categories studied, including yolk sac tumor, embryonal carcinoma, and choriocarcinoma. The tumor cells in both testicular and mediastinal embryonal carcinoma showed strong positivity for the CD30 antigen; however, strong positivity for this marker was also observed in 6 of 25 yolk sac tumors and in scattered individual tumor cells in 4 of 63 seminomas. The results of this study show that significant differences exist between the immunostaining patterns of mediastinal and testicular seminomas, suggesting that the former may be characterized by a more mature phenotype than their testicular counterparts. Also, CD30 expression may not be necessarily restricted to embryonal carcinomas and occasionally may be observed in yolk sac tumors and seminoma cells, supporting the close histogenetic relationship that exists among these tumor types.

Editorial Comment: Extragonadal germ cell tumors, although relatively rare, have a signifi- cantly worse prognosis than their gonadal counterparts. The authors studied 120 archival cases of gonadal and extragonadal germ cell tumors with a panel of immunohistochemical markers, including broad-spectrum keratin, a-fetoprotein, placental-like alkaline phosphotase, P-HCG and CD30. Mediastinal seminomas demonstrated increased positivity to low molecular weight keratin but did not reveal significant differences in staining for gonadal versus mediastinal nonseminomatous germ cell tumors. CD30 immunoreactivity was identified in seminoma and yolk sac tumor in addition to embryonal carcinoma.

Jerome P. Richie, M.D.

Sertoli Cell Tumors of the Testis, Not Otherwise Specified. A Clinicopathologic Analysis of 60 Cases

R. H. YOUNG, D. D. KOELLIKER AND R. E. SCULLY, James Homer Wright Pathology Laboratories, Massachu- setts General Hospital, Harvard Medical School, Boston, Massachusetts

h e r . J. Surg. Path., 2 2 709-721, 1998 Sixty Sertoli cell tumors of the testis, excluding large cell calcifying and sclerosing subtypes, are

described. Patient age ranged from 15 to 80 years (mean, 45 years). The initial manifestation was usually a testicular mass; in 14 cases it had been enlarging slowly for a period of up to 14 years (mean 3.7 years). Only five patients had testicular pain. Four patients had metastatic disease at the time of presentation. All the tumors were unilateral and ranged from 0.3 cm to 15 cm (mean 3.6 cm). They were typically well circumscribed. Sectioning usually disclosed firm, tan-gray, white, or yellow tissue with areas of hemorrhage and a minor cystic component in approximately one third. Microscopic evaluation usually revealed diffuse sheets or large, nodular aggregates of tumor cells, within which solid or hollow, sometimes dilated, tubules and, less often, cords were usually at least focally identifiable. A relatively acellular, often vascular, fibrous to hyalinized stroma was frequently conspicuous. The tumor cells typically had moderate amounts of pale

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