[831] The Utility of Microscopic Findings and Immunohistochemistry in the Classification of Necrotic Testicular Tumors: A Study of 11 Cases

JS Miller, TK Lee, JI Epstein, TM Ulbright. Johns Hopkins Hospital, Baltimore, MD; Indiana University School of Medicine, Indianapolis, IN

Background: Necrotic testicular tumors are relatively frequent and can present a significant diagnostic challenge. Because of the differing treatment modalities for seminomas versus non-seminomas, accurate histologic diagnosis is critical.
Design: Eleven totally (9) or almost totally (2) necrotic testicular tumors were retrieved from our consult files. They were evaluated for histologic features and, when material was available, by immunostaining with 7 antibodies: keratin (AE1/AE3), OCT4, PLAP, AFP, CD117, CD30, and S100. A stain was scored as positive when there was distinct reactivity in a cellular distribution in the necrotic zone; only nuclear reactivity was scored for OCT4 and membrane reactivity for CD117 and CD30.
Results: Patients averaged 34 years old (range, 16-63). Mean tumor size was 16 mm (range, 7-30). All patients presented with unilateral testicular masses (6 right, 5 left); 2 also had acute pain. The combination of histological features, immunostains and, in 1 case, serum AFP permitted classification of 8 tumors (4 seminomas, 3 embryonal carcinomas, 1 yolk sac tumor). Three were not classifiable. The necrotic seminomas lacked associated coarse intratubular calcifications and were positive for OCT4 (4/4) and CD117 (3/3) but negative for keratin (4/4) and CD30 (4/4). The necrotic embryonal carcinomas had associated coarse intratubular calcifications and were positive for keratin (2/3), OCT4 (2/2) and CD30 (3/3). In 1 unclassifiable tumor, only OCT4 was positive in the necrotic tumor. We did not find PLAP, AFP and S100 stains useful, although S100 did highlight tumor ghosts in 1 case. Other features present in most cases included IGCNU (6/10), tubular atrophy/hyalinization (10/10), tumor ghost cells (9/10), scar (9/10) and inflammation (9/10). Of the 5 patients with available follow-up, 3 were free of disease at 1, 5 and 8 yrs after orchiectomy (all necrotic seminomas). One patient with yolk sac tumor (age 63 years) developed multiple widespread metastases after 15 months and died of disease. The final case was initially misinterpreted as testicular infarction [with] no malignancy and 16 months later the patient developed a large retroperitoneal seminoma.
Conclusions: Most totally necrotic testicular tumors can be placed into clinically important groups by assessment for coarse intratubular calcifications and staining reactions for keratin, OCT4, CD117 and CD30.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 1:00 PM

Poster Session II # 98, Monday Afternoon