[Neuroendocrine Tumor Possibly Originating from the Kidney : A Case Report].

A 40-year-old woman was referred to our hospital with right lower back pain as the chief complaint. Contrast-enhanced computed tomography (CT) showed a partially-solid tumor within a cyst measuring approximately 6 cm in diameter in the right renal hilum. The solid part was enhanced in the early phase and contrast medium was washed out earlier in the solid part than in the parenchyma in the equilibrium phase. Plain CT revealed partial cyst wall calcification. A soft tissue shadow approximately 10 mm in diameter in the dorsal inferior vena cava at the upper pole of the kidney and a solid tumor adjacent to the iliopsoas muscle and the kidney were detected. We performed radical nephrectomy and lymph node dissection with transperitoneal approach. The histopathological diagnosis was neuroendocrine tumor. Her clinical course has since been observed on an outpatient basis, for nearly 10 months to date, without any recurrence.