PASH on Breast Ultrasound and MRI

IMAGING FINDINGS:​

​Breast ultrasound shows an oval heterogenous mixed echogenicity circumscribed mass that could easily be mistaken for normal fibroglandular tissue. Subtraction images on breast MRI demonstrate regional nonmass enhancement along the upper outer left breast.
 
WHY IT MATTERS:

1. PASH stands for Pseudo-Angiomatous Stromal Hyperplasia. It is a benign process that may present as a palpable mass or may be initially identified on screening mammography.
2. PASH commonly presents as a developing asymmetry on mammography (often in the upper outer quadrant). It’s appearance on breast ultrasound can also be very subtle.

FURTHER READING:
Pseudoangiomatous Stromal Hyperplasia: Imaging Findings With Pathologic and Clinical Correlation (AJR, 2010)