Renal inflammatory pseudotumor.

A previously healthy 37-year-old man had evaluation of abdominal pain, which had persisted after abrupt onset with fever and hematuria. Although the fever and hematuria had spontaneously resolved after 1 week, the abdominal pain had worsened over a 4-month period. Predicated upon computed tomography and with a presumed diagnosis of renal cell adenocarcinoma, left radical nephrectomy was done. Histopathologic analysis was negative for malignancy but compatible with inflammatory pseudotumor of the urogenital tract--a pathologic entity that is common in the urinary bladder and prostate gland but is rarely diagnosed in the kidney.