(Pseudoangiomatous stromal hyperplasia):

Pseudoangiomatous stromal hyperplasia (PASH) is frequently a microscopic incidental finding in breast biopsies. However, it may also produce a lump. It should be diagnosed by a needle biopsy or by removal of the lump.

In a recent review of 40 women with PASH, it occurred aged 14 to 67 years (mean, 37 years). All but one of these women found a lump. In one woman it was found by mammography. The lump often feels like a fibroadenoma.

The cause of PASH is unknown. It can go away by itself but if it is causing problems then simple removal is adequate treatment initially and for infrequent recurrences. Diffuse PASH occasionally may very occasionally need mastectomy.