Renal cell carcinoma in the presence of adult polycystic kidney disease.

A case of autosomal dominant polycystic kidney disease associated with widely metastatic renal cell carcinoma is reported. The patient had presented with pneumothorax, weight loss, leukocytosis, lytic bone lesions, and hypercalcemia. Despite intensive diagnostic search for a neoplasm, no firm evidence of malignancy was found. However, at the autopsy, widely metastatic, papillary renal cell carcinoma was found originating in the left kidney. Many metastases showed central necrosis mimicking small cysts.