Breast, fascicular pseudoangiomatous stromal hyperplasia

Pseudoangiomatous stromal hyperplasia (PASH) is a benign proliferation of stromal myofibroblasts, so named because its growth between stromal fibres can mimic a growth of lymphatic or blood vessels. It is thought to be a hormone-related reactive process. In this case, prominent fascicular and cellular growth partially obscures the underlying PASH.