ABSTRACT
Objective To analyze the features of diagnosis, treatment and prognosis of primary renal neuroendocrine tumors, and to improve the understanding of primary renal neuroendocrine tumors. Methods From January 2008 to June 2015, 5 cases of primary renal neuroendocrine tumors were hospitalized and their data was analyzed retrospectively, with 1 male 4 females, aged 40-73 years with the middle age of 48 years.Tumors were all located in the left kidney, whose diameters arranged from 4 to 9 cm, with an average of 6.5cm.One case presented with hematuria, one case was identified because of abdominal pain, and the other three cases were identified via physical examination.Four cases underwent a renal contrast-enhanced ultrasound, which indicated a medium-hypoechoic mass in three cases and a hyperechoic mass in one case.All five cases underwent CT scan, presenting irregularly shape and density. Calcification was found in three cases on plain scanning.Significantly heterogeneous enhancement was found in three cases and moderate heterogeneous enhancement was found in one case on enhanced scanning. Results All five cases underwent operations, with two cases undergoing radical nephrectomy and three cases undergoing partial nephrectomy.Pathological examination showed three cases of tumor cells arranged in a nest slug or ribbon-like infiltrative growth, with no or rare mitosis and no necrosis, which is consistent with renal carcinoids.Three out of 4 renal hilar lymph nodes containing tumor cells were identified in one case. The tumor cells in another case exhibited a ribbon-like arrangement, with some round nuclei, no significant atypia, and rare mitosis, which is consistent with renal atypical carcinoid.Two out of two renal hilar lymph nodes containing tumor cells were identified in this case. The tumor tissue of one case showed morphologically uniform, medium-sized cells arranged in nest slug form with necrosis, a high nuclear cytoplasm ratio, an obvious allotype and frequent mitosis, which is consistent with renal small cell carcinoma.The immunohistochemistry of the five cases indicated synaptophysin( Syn) and chromogranin A ( CgA) positive in varying degree.One case of renal carcinoid relapsed approximately 78 months after partial nephrectomy, following with radical surgery.The other two cases were followed up for 8 or 27 months and no recurrence or metastasis was detected.One case of renal atypical carcinoid was followed up for 4 months after radical nephrectomy and no recurrence or metastasis was detected.One case of renal small cell carcinoma died of multiple organ failure 11 months after radical nephrectomy plus hepatic metastatic carcinoma radio-frequency ablation approximately.Conclusions Primary renal neuroendocrine tumors are rare clinically. Renal neuroendocrine tumors may be expressed as carcinoid, atypical carcinoid or small cell carcinoma, and the clinical manifestations, pathological characteristics and prognosis varied.Primary renal carcinoids may be treated by surgery with a nice prognosis.Patients with primary renal small cell carcinoma require comprehensive treatment, and their prognosis is poor.