Pseudoangiomatous Stromal Hyperplasia (PASH) of the Breast: A Clinicopathological Study of 79 Cases

Background. Pseudoangiomatous stromal hyperplasia (PASH) of the breast is a benign lesion that can present as a palpable nodule or as an incidental finding in breast biopsies. Design. The study comprised 79 cases diagnosed at Loyola University Medical Center from 2002 to 2009. The pathology slides were reviewed to document the distribution, type, and association with preneoplastic or neoplastic epithelial lesions. Z-test for independent proportions is used for analysis. Results. A total of 76 patients were female and 3 were male. In all, 59.8% of patients presented with a breast mass and in 40.2% the lesion was an incidental finding. Classical PASH morphology was seen in 97.6% and proliferative PASH in 2.4%. Associated epithelial lesions were benign proliferative changes in 60.4%, atypical ductal and atypical lobular hyperplasia in 25.6% and infiltrating carcinoma in 11% of cases. Conclusions. Based on these results, extensive sampling of biopsy specimen with PASH and appropriate clinical and radiologic follow-up is recommended.