Pseudoangiomatous stromal hyperplasia (PASH) of the breast: A case series.

Pseudoangiomatous stromal hyperplasia (PASH) is a benign mesenchymal proliferative lesion of the breast. In 2005, only 109 cases have been reported since its initial description in 1986 by Vuitch et al. when it presented in one patient as a palpable breast mass. We retrospectively reviewed data from 2020 to 2023 of patients diagnosed with PASH by surgical excision. Our 13 cases represent one of the most numerous reported from a single institution. All histologic specimens were examined by a single pathologist. All patients had breast masses on imaging or were clinically evident. Eleven of the patients (84.6%) were diagnosed by surgical excision, whilst only two (15.4%) were diagnosed by core needle biopsy. Imaging revealed no strongly distinctive features for PASH. The age of the patients ranged from 25 to 68 years. All but one of the women were premenopausal at the time of diagnosis. This study suggests that PASH is a lesion whose diagnosis is often incidental and the recommended treatment is more commonly surgical.