Primary neuroendocrine tumor of the testis: a study of clinicopathological features.

This study aimed to explore the clinicopathological characteristics and differential diagnosis of primary neuroendocrine tumor (G1) of the testis. In this paper, we analyze the clinical, histomorphological and immunohistochemical findings, treatment and prognosis of a patient with primary neuroendocrine tumor of the testis, and discuss the relevant literature. A 52-year-old man presented with a painless testicular swelling since 6 months. Histopathological examination showed that the tumor cells were arranged in island and beam patterns. The tumor cells were uniform, polygonal and had moderately eosinophilic cytoplasm and fine granular nuclear chromatin. Immunohistochemical staining showed that the tumor cells were positive for cytokeratin, CD56, synaptophysin and chromogranin A, and negative for inhibin, placental alkaline phosphatase and alpha-fetoprotein. Primary neuroendocrine tumor of the testis is a rare tumor with characteristic imaging features. Its accurate diagnosis depends on the morphological and immunohistochemical findings. These tumors should be differentiated from metastatic neuroendocrine carcinomas, teratomas with carcinoid, seminomas, Sertoli cell tumors and granulosa cell tumors. The treatment of most primary neuroendocrine tumors involves surgical resection combined with other therapies and usually results in a good prognosis.