A unique association of renal carcinoma with sarcoid reaction in the kidney

Sarcoid reactions have been described in association with lymphomas and rarely with other solid tumors. We describe a patient with renal papillary adenocarcinoma and prominent sarcoid-like granulomatous infiltration of the ipsilateral and most likely the contralateral kidney. There was no evidence of extrarenal granulomas. This is the first description of impairment in renal function in a patient with renal carcinoma and with sarcoid reaction to this tumor isolated in the kidney.