A 14-year-old girl consulted for multiple breast nodules which were found to result from Cowden's disease, also called multiple hamartomatosis. Mammography and sonography examinations were completed with nuclear magnetic resonance imaging after injection of paramagnetic contrast product. Cowden's disease is a rare condition resulting in the development of tumors in genodermatous tissue; The cause remains unknown. In cases involving the breast, cutaneous lesions are markers of precancerous development since cancer occurs in 28 to 30% of these cases.