[793] Immunohistochemical Studies of Metastatic Germ Cell Tumors in the Retroperitoneal Dissection Specimens: A Sensitive and Specific Panel

Z Bing, T Pasha, JE Tomaszewski. Hospital of the University of Pennsylvania, Philadelphia

Background: SALL4 and glypican 3 (GPC3) are two recently described germ cell tumor markers. In this study, we evaluated the usefulness of a panel of immunohistochemical markers (SALL4, GPC3, CD30 and D2-40) in the differential diagnosis of retroperitoneal dissection specimens for germ cell tumors.
Design: Retroperitoneal lymph node dissection specimens were stained for SALL4, GPC3, CD30 and D2-40. The specimens included 17 cases of metastatic testicular germ cell tumors, 10 cases of metastatic melanoma, 14 cases of lymphoma, and 8 cases of metastatic carcinoma.
Results: For SALL4, All of the seminoma (N=7), embryonal carcinoma (EC) (N= 8) and yolk sac tumor (YST) (N=4) showed strong nuclear staining (see table). Metastatic carcinoma and melanoma, and lymphoma were negative. For GPC3, only one out of 7 seminoma showed focal positivity. 4 out of 9 EC showed weak positivity. All 4 YST were positive. All of the melanoma were negative. 5 out of 8 cases of carcinoma were weakly positive. Only 1 out of 14 cases of lymphoma was weakly positive. The staining was cytoplasmic. For D2-40, all of the seminoma (N=7) were positive. The staining was strong and membranous. 4 out of 9 EC showed focal and weak cytoplasmic staining. Two cases of YST were negative. All of the melanoma and carcinoma were negative. Only 1 out of 14 cases of lymphoma was focally and weakly positive. For CD30, all 8 cases of EC were positive. All of the seminoma, YST, melanoma, and carcinomas were negative. 3 out of 14 cases of lymphoma were positive, one was strong and diffuse, and two were weak and focal. All of the positive lymphomas were subtyped as diffuse large cell lymphoma.

Immunohistochemical study of retroperitoneal dissection specimens
SALL4 (%) (#positive/total)GPC3(%)(#positive/total)D2-40(%) (#positive/total)CD30(%) (#positive/total)
Seminoma100 (7/7)14 (1/7)100 (7/7)0 (0/7)
EC100 (8/8)44 (4/9)44 (4/9)100 (8/8)
YST100 (4/4)100 (4/4)0 (0/2)0 (0/2)
Melanoma0 (0/10)0 (0/9)0 (0/10)0 (0/10)
Carcinoma0 (0/7)63 (5/8)0 (0/6)0 (0/8)
Lymphoma0 (0/14)7 (1/14)7 (1/14)21 (3/14)

Conclusions: Immunohistochemical stains for SALL4, GPC3, D2-40 and CD30 are a sensitive and specific panel, which may facilitate in the differential diagnosis of metastatic germ cell tumors in retroperitoneal dissection specimens.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 101, Monday Afternoon


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