Malakoplakia of kidney simulating renal neoplasm

In a nine-year-old girl with renal hypertension and a urinary infection, angiographic studies of the left kidney suggested an intrarenal pheochromocytoma. After nephrectomy, the kidney was found to contain only a cystic lesion characterized by multiple small, friable excrescences. Under the light microscope these appeared to be formed by granulovacuolated macrophages. Electron microscopy showed intracytoplasmic inclusion identified as Michaelis-Gutmann bodies in various stages of formation. Images suggestive of degraded bacteria were also observed within phagolysosomes.