Benign Breast Lesions That Mimic Cancer: Determining Radiologic-Pathologic Concordance

Julia Mario, BA; Shambhavi Venkataraman, MD; Vandana Dialani, MD; Priscilla J. Slanetz MD, MPH


Appl Radiol. 2015;44(9):28-32. 

In This Article

Pseudoangiomatous Stromal Hyperplasia (PASH)

PASH, a type of spindle cell lesion, is a benign growth of stromal myofibroblasts most commonly found in premenopausal women.[36] Patients may present with a painless palpable lump or PASH may be discovered incidentally on imaging. On mammography PASH typically presents as a non-calcified oval mass or as a developing focal asymmetry (Figure 4e).[37] On ultrasound it most commonly presents as a well-circumscribed oval hypoechoic mass.[36,37] Histologically PASH is characterized by slit-like spaces in the stroma lined by spindle-shaped myofibroblasts. These slit-like spaces are easily mistaken for vascular spaces (hence the name pseudoangiomatous), and may be misinterpreted as angiosarcoma.[37] The pathogenesis is poorly understood, however ovarian hormones may play a role. PASH can enlarge, but is benign and does not need to be excised, although some patients opt for surgical removal.