The author, on the basis of the full study of 2 families, is able to take a clear position with regard to the nosology of Spiegler''s cylindroma and of Brooke''s epithelioma. Genetically and clinically both disorders can be classed among the hereditary, pleitropic, auto-somal affections with irregular dominance. Thus, the nosological unity of these 2 diseases, which can be easily differentiated histologi-cally, is established.