Primary carcinoid tumor of the testis: immunohistochemical, ultrastructural and DNA flow cytometric study of two cases.

Primary testicular carcinoid tumor, occupying 0.23% of testicular neoplasm, is a rare and indolent neoplasm with the potential for distant metastasis. We present two cases of primary pure carcinoid tumor of the testis. Both patients were 36 years old. Physical examination revealed testicular mass with and without tenderness. The preoperative serum levels of beta-human chorionic gonadotropin and alpha-fetoprotein were normal and neither patient had carcinoid syndrome. The tumors measured 7.5x6x4 cm and 5.5x5x4 cm in size. Histologically, immunohistochemically and ultrastructurally, the tumors showed typical features of the carcinoid tumor. Case 1 showed extensive tumor necrosis and vascular invasion. DNA flow cytometric analysis showed aneuploidy with DNA index of 1.47 and S+G2M of 14.0% in case 1 and tetraploidy with DNA index of 1.96 and S+G2M of 22.1% in case 2. Both patients have been well without any signs of metastasis after operation for 24 months in case 1 and for 16 months in case 2.