Fast-growing pseudoangiomatous stromal hyperplasia of the breast: report of a case.

Pseudoangiomatous stromal hyperplasia (PASH) is a rare type of benign mesenchymal proliferative disease of the breast. Histologically, it is composed of a proliferation of spindle cells with inter-anastomosing vascular-like arrangement in the interlobular or interductal stroma. Clinically, pseudoangiomatous stromal hyperplasia is usually found in premenopausal women as a discrete, painless mass, which is firm and movable. We report a case of pseudoangiomatous stromal hyperplasia of the breast, which mimicked a malignant mass in that it grew rapidly and ultrasonography showed a lobulating contoured heterogeneous echotexture.