OBJECTIVETo study the biological and clinicopathological characteristics of neuroendocrine tumors of the kidney (KNETs) for improving the diagnosis and treatment of this diseases.

METHODSThe pathological and clinical features of 3 KNET cases treated in Sun Yat-sen University Cancer Center between 1999 and 2010 were summarized, and the the histogenesis, pathological and immunohistochemical characteristics, diagnosis and prognosis of KNETs were analyzed with review of all reported cases worldwide.

RESULTSAll the 3 patients had waist masses but without clinical manifestations of carcinoid syndrome, and underwent resection of the tumors. The postoperative pathological diagnosis was carcinoid carcinoma in 2 patients and Wilms tumor with neuroendocrine differentiation in 1 patient. Immunohistochemical examination showed that the tumors were positively stained for cytokeratin and vimentin; positivity for neuron-specific enolase and synaptophysin was found in 2 cases, and chromogranin positivity in 1 case. After the operation, 1 patient received chemotherapy, 1 had biotherapy and radiotherapy, and 1 received no further treatment. During the follow-up from 6 months to 6 years, 1 patient died of tumor metastasis, 1 was lost to follow-up, and 1 showed no recurrence until now.

CONCLUSIONSKNETs has specific pathological characteristics. Abdominal masses, acute loin pain and hematuria are the most common symptoms. A definite diagnosis relies on pathology and immunohistochemistry. For early carcinoid carcinoma, surgical resection is curable, but in advanced cases, the prognosis is poor and comprehensive therapy is recommended.