Concurrent Eosinophilic Solid and Cystic Renal Cell Carcinoma and Angiomyolipoma with Epithelial Cysts: A Rare Synchronous Occurrence of Two Extremely Rare Distinct Entities

Summary: Distinction of benign from malignant biliary lesions can be diagnostically challenging, particularly on small core biopsies due to significant morphologic overlap between benign intrahepatic bile duct proliferations (e.g., bile duct adenoma) and well differentiated intrahepatic cholangiocarcinoma (ICC). The aim of our study was to evaluate if the use of insulin like growth factor II mRNA binding protein-3 (IMP3) and Ki-67 may help in distinguishing benign from malignant intrahepatic bile duct proliferations on core biopsies.