RESUMO
BACKGROUND: Primary carcinoid tumors are rare and constitute 0.23% of all testicular tumors. We report a case of primary carcinoid tumor of testicular localization, with a review of the literature. CASE PRESENTATION: A 29-year-old man, without specific ascendants, consulted the urology department for progressive scrotal swelling of 6 months, associated with pain. After surgery, histology showed diffuse tumor proliferation composed of small round monotone cells with hyperchromatic nuclei evoking undifferentiated carcinoma. Immunohistochemistry showed that tumor cells were positive for chromogranin A and negative for placental alkaline phosphatase and α-fetoprotein. CONCLUSION: Primary neuroendocrine carcinoma of the testis is a very rare malignant tumor. Immunohistochemistry contributes to its diagnosis in relation to other metastatic neuroendocrine carcinomas, carcinoid tumor teratomas, seminoma, and Sertoli cells.