title: [Primary neuroendocrine tumor of the testis: clinicopathological study of 7 cases].
abstract: OBJECTIVE
  To investigate the clinicopathologic characteristics, diagnosis, differential diagnosis and treatment of primary neuroendocrine tumor (NET) of the testis.
  
  
  METHODS
  Using light microscopy and immunohistochemistry, we studied 7 cases of primary NET of the testis, reviewed relevant literature, and analyzed the clinical manifestations, histomorphologic and immunohistochemical characteristics, treatment and prognosis of the tumor.
  
  
  RESULTS
  The 7 male patients, at the mean age of 40.6 years, all presented with testicular painless masses, none accompanied with carcinoid syndrome. Histologically, the uniform tumor cells were arranged in trabecular, island, solid and/or flake structures and locally in a tubulo glandular pattern, round and polygonal in shape, with a small amount of lipid vacuoles in the eosinophilic cytoplasm. The cells had round nuclei with fine chromatin and rarely identified mitosis. Immunohistochemical staining showed that the tumor cells were positive for Syn, CgA, NSE and CK, with a Ki-67 positive rate of < 2%.
  
  
  CONCLUSIONS
  Primary NET of the testis is a rare and low-grade malignancy. Early diagnosis and surgical resection are essential for good prognosis. Immunohistochemistry helps its diagnosis and differential diagnosis from other metastatic neuroendocrine carcinoma, teratomas with carcinoid, seminoma, and Sertoli cell tumor.
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Fei-Fei
authors: FF
authors: Liu
authors: Department of Pathology, General Hospital of Jinan Military Region, Jinan, Shandong 250031, China.
authors: Jin-Feng
authors: JF
authors: Zheng
authors: Department of Pathology, General Hospital of Jinan Military Region, Jinan, Shandong 250031, China.
authors: Lu-Ting
authors: LT
authors: Zhou
authors: Department of Pathology, General Hospital of Jinan Military Region, Jinan, Shandong 250031, China.
authors: Cui-Cui
authors: CC
authors: Wang
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Jian-Jun
authors: JJ
authors: Wang
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Qin
authors: Q
authors: Shen
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Bo
authors: B
authors: Yu
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Heng-Hui
authors: HH
authors: Ma
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Jian-Dong
authors: JD
authors: Wang
authors: Department of Pathology, Nanjing General Hospital of Nanjing Military Region/School of Medicine, Nanjing University, Nanjing, Jiangsu 210002, China.
authors: Qun-Li
authors: QL
authors: Shi
mesh_terms: D000328:Adult; D002276:Carcinoid Tumor / Q000175:diagnosis / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000473:pathology*; D011379:Prognosis; D013736:Testicular Neoplasms / Q000175:diagnosis / Q000473:pathology*