Angiomyolipoma with Epithelial Cysts (AMLEC) of the Kidney

A 49-year-old man was demonstrated to have two tumors in the right kidney by computed tomographic scan during an examination for cholelithiasis. One was a fat rich solid tumor which was clinically diagnosed as angiomyolipoma, and the other was an unconfirmed cystic tumor. Cholecystectomy and radical nephrectomy were performed. Based on pathological findings, the solid tumor was diagnosed as common angiomyolipoma and the cystic tumor as angiomyolipoma with epithelial cysts (AMLEC). The cystic tumor consisted of 3 components : an epithelial cyst lined with single flat to cuboidal cells, a subepithelial compact stroma and an external layer of muscle predominant angiomyolipoma. Immunohistochemical examinations showed strong intense staining of pan-cytokeratin in the epithelium lining the cyst. The subepithelial compact stroma was stained with both CD10 and HMB45. The muscle predominant angiomyolipoma exhibited expression of HMB45. AMLEC is a recently recognized rare variant of angiomyolipoma