Bellini duct carcinoma of the kidney--a case report.

Bellini duct carcinoma (BDC), originating from the principal cells of the collecting duct of the kidney, accounts for only 1% of renal carcinomas. This lesion is a histogenetically, morphologically and cytogenetically defined entity. We report an eosinophilic variant of BDC. A 71-year old male presented with a tumor in the right kidney. Nephrectomy was performed. BDC (stage pT3a N0 M0 G2, based on UICC classification) was diagnosed. Electron microscopy revealed an abundance of mitochondria. Intranuclear rodlets were seen. Neuroendocrine differentiation was not demonstrated. After a three-year observation period, there are no signs of recurrence or metastases.