Primary Well-Differentiated Neuroendocrine Tumor of the Kidney

Primary neuroendocrine tumors (NET) of the kidney are rare. They present with varied symptoms, making their diagnosis difficult clinically as well as pathologically. We present to you the case of a renal NET, which presented in a young female patient. A 48-year-old female patient came with an incidentally detected right renal mass during the evaluation of a nonspecific gynecological problem. She underwent contrast-enhanced computed tomography (CT) of the abdomen, which showed a 57*45*34 mm mass with enlarged retrocaval and aortocaval nodes (25*12 mm). Renal cell carcinoma was suspected as per the CT findings, and metastatic workup in the form of FDG PET CT was done in view of the unusually enlarged nodes. She underwent robot-assisted radical nephrectomy along with lymph node dissection. Surgery was uneventful, and she recovered well in the postoperative period. In the final pathology, there was confusion regarding the diagnosis, and further immunohistochemistry (IHC) was recommended by the pathologist. IHC showed synaptophysin positive, chromogranin negative, CD56 focally positive with Ki-67 of 2-3%, which was suggestive of low-grade NET of the kidney. Lymph nodes were negative. She was kept on follow-up and a Ga 68-DOTANOC scan at 3 months showed no evidence of disease. Diagnosis and management of NET of the kidney still remains a debatable and controversial topic in view of its rarity. High index of suspicion needs to be observed in patients presenting with carcinoid syndrome and a renal mass. Nuclear scans like PET scan and DOTANOC scan can accurately stage the disease. Management includes partial or radical nephrectomy depending on the tumor characteristics. Further studies are required to optimize the treatment protocols for these patients.