Pseudoangiomatous Stromal Hyperplasia of Breast
Image Description
Myofibroblasts lining the slit-like spaces in PASH may resemble endothelial cells; however, their nuclei are attenuated and lack cytologic atypia or increased mitotic activity. They are positive for CD34 and vimentin, variably reactive for actin, desmin and calponin and negative for vascular markers. Some cases of PASH are cellular and resemble myofibroblastoma.