Acute renal failure secondary to small cell lung cancer with tumor infiltration of the kidneys.

Acute renal failure secondary to tumor infiltration of the kidneys is uncommon and largely described in patients with lymphoma or leukemia. We report a 64-year-old man previously diagnosed with limited stage small cell lung cancer who presented with acute renal failure (ARF). Renal imaging showed bilateral enlargement with features suggestive of an infiltrative process. A kidney biopsy established the diagnosis of metastatic small cell lung cancer with diffuse renal parenchymal infiltration. This case emphasizes the rare potential for cancers to metastasize to the kidneys, which can result in ARF. Early recognition of this cause of ARF is crucial, in particular, when the tumor is amenable to chemotherapy or irradiation.