Papillary renal cell carcinoma with malakoplakia: A unique case

The reported cases of malakoplakia concurrent with renal cell carcinoma (RCC) are exceedingly rare. Two prior cases of malakoplakia have been previously reported in patients with clear cell renal cell carcinoma. We report the third case of concurrent malakoplakia and RCC in the same kidney and the first case of malakoplakia with the papillary type of renal cell carcinoma. Our case occurred in a 73-year-old woman with urinary tract infection and diabetes who was found to have a large renal mass on imaging and underwent radical nephrectomy. Malakoplakia was present both within the tumor and in portions of kidney away from the tumor itself. The microscopic features of malakoplakia included PAS-positive histiocytes with calcium positive Michaelis-Gutmann bodies which were also seen on electron microscopy. Since malakoplakia can mimic renal cell carcinomas (RCC) clinically and pathologically, our case highlights the importance of an awareness of the possible concurrence of these two diagnoses for accurate histopathologic diagnosis and treatment of patients with both diseases.