The PJ, introduced by Rosen in the 1980, is a benign and localized mammary lesion in female under 30 years old. The most important clinical and histological features are: • Diagnosis in juvenile ag • A mass clinically localized • A nodule with histologic features of cyst, benigne hyperplasia of ductal epithelium and galactophorus ducts dilatation (Swiss cheese disease). There is a correlation between patients with PJ and breast cancer there is an increment of breast cancer in familiares of patients with PJ. There is an increment of the risk to develop a K in situ in patients with PJ and apocrine metaplasia and/or adenomatosis and/or atypical mastoplasia. We describe the diffuse PJ in a girl of 23 years old from the 1996 to 2002.