[Metanephric epithelial hamartomas. A contribution to their morphology, evolution and significance (author's transl)]

In the uninvolved kidney parenchyma of three cases with Wilms' tumor neoplastic metanephric aberrations were found which represent regressive forms of the nodular renal blastema-nephroblastomatosis complex. Their histopathologic features are demonstrated. They are designated as simple or diffuse metanephric epithelial hamartomas. Small lesions show involution resulting in scars. In the central parts of larger lesions cysts and adenomas were detected. The latter were multicentric and revealed compact-epithelial, papillary-psammomatous, cystic-multilocular and tubulo-papillary forms. Their origin, possible evolution, relationship to nephroblastoma as well as their significance are discussed.