Mixed Epithelial & Stromal Tumor
Section Editor: Dharam M. Ramnani, MD
Virginia Urology, Richmond, VA, USA
Image Description
Mixed epithelial and stromal tumor (MEST): The image shows variably-sized cysts lined by flattened or cuboidal epithelium with focal hobnailing. The intervening stroma is ovarian type. Most cases of MEST of the kidney behave in a benign fashion. Rare cases may undergo malignant transformation in either the epithelial or the stromal component.