PASH is a rare benign proliferative lesion of the mammary stroma. They are usually detectable on mammography and may be seen as a partially circumscribed mass, rarely irregular.

On ultrasound, they present as an oval, well defined hypoechoic mass, rarely with cystic spaces - like our case. Less commonly, they are heterogeneous or hyperechoic.

This particular lesion was biopsied using ultrasound guidance and surgically excised afterwards. Histopathology results confirmed pseudoangiomatous stromal hyperplasia (PASH).