Fat-Containing Renal Cell Carcinoma Mimicking Angiomyolipoma: A Radiological and Histopathological Diagnostic Challenge

A well-marginated fat-containing renal lesion gives strong suspicion of renal angiomyolipoma (RAML) that usually requires no surgical intervention. Radiologically, renal masses with a large amount of fat can rule out renal cell carcinoma (RCC). Calcifications are very infrequent in RAML. However, the presence of calcifications in a fat-containing renal lesion is highly suggestive of RCC. These lesions should undergo surgical resection and histopathological assessment to reach the right diagnosis and avoid poor outcomes if diagnosed late. We present a case of bilateral renal tumors, in which one of them radiologically contained abundant fat with calcifications on CT scan, which was confirmed to be an RCC on histopathological examination.