Breast Imaging Chameleon: Pseudoangiomatous Stromal Hyperplasia Presenting as Breast Malignancy

Abstract

Pseudoangiomatous stromal hyperplasia (PASH) is a benign mesenchymal proliferative lesion of the breast, often an incidental finding on breast biopsy specimens and rarely presents as a palpable lump. The case being reported is interesting as a lactating female presented with gross left breast enlargement due to a huge firm mass with skin thickening and palpable left axillary lymph nodes. A provisional diagnosis of left breast malignancy was made and the patient extensively worked up with ultrasound, CT scan, bone scan and core biopsy. The histopathology, however, revealed PASH of the breast. There was no invasive or in situ malignancy. The patient was successfully managed conservatively.

Keywords: benign; breast; malignancy; palpable lump; pseudoangiomatous stromal hyperplasia; ultrasound.

Figure 1. Gray scale ultrasound image of left breast and axilla

(A) Image shows a solid, circumscribed mass (thin white arrows) predominantly in upper outer quadrant of left breast with few cystic spaces (curved arrow). (B) Image shows abnormal left axillary lymph node with asymmetric cortical thickening (short thick arrow) and displaced hilum.

Figure 2. Contrast-enhanced CT scan

Axial (A) and coronal (B) images show large enhancing soft tissue mass in the left breast (thick white arrows). Marked skin thickening is also noted (long white arrow) as well as left breast edema.

Figure 3. Photomicrograph (H&E and immunohistochemical stain)

(A) Linear cores of benign breast tissue exhibiting ducts and lobule with surrounding hyalinized stroma (arrows. (B) Slit-like spaces mimicking thin blood vessels frequently seen in stroma (arrows). (C) These spaces are line by bland spindle shape cells (arrow). (D) The lining cells demonstrate positive expression for CD-34 immunohistochemical stain.