Giant kidney worms in a patient with renal cell carcinoma.

Dioctophyma renale (D. renale), or giant kidney worms, are the largest nematodes that infect mammals. Approximately 20 cases of human infection have been reported. We present a case of a 71-year-old man with a recent history of unintentional weight loss and painless haematuria, passing elongated erythematous tissue via his urethra. CT revealed a left renal mass with pulmonary nodules and hepatic lesions. On microscopy, the erythematous tissue passed was identified as D. renale. On subsequent renal biopsy, pathology was consistent with renal cell carcinoma. This is the first reported case of concomitant D. renale infection and renal cell carcinoma, and the second reported case of D. renale infection of the left kidney alone.