Breast pseudoangiomatous stromal hyperplasia challenges

Pseudoangiomatous stromal hyperplasia (PASH) is a rare proliferative breast disease. It is characterized by fibrosis of the mammary stroma surrounding breast ducts and lobules with formation of anatomizing capillary-like spaces lined by myofibroblastic cells. Commonly, patients present with a palpable breast mass or continuous breast enlargement. We report a case of a 25 year old lady who presented with painless unilateral swelling of her right breast. Ultrasonography showed heterogeneous, hypoechoic benign appearing breast tissue. Histopathology revealed dense collagenous stroma separated by slit like spaces that were lined by bland spindle cells showing no cytological atypia. With immunohistochemistry, these cells were positive for CD-34 and SMA and negative for the endothelial marker CD-31. Some of these cells were also positive for ER and PR.