A 49-year-old woman, with a medical history of rheumatism, was admitted to our hospital with chief complaints of bilateral enlargement and redness of breasts. She underwent weekly breast examinations. Mammography findings were reported as category 3 for both breasts. Breast ultrasonography, magnetic resonance imaging, and chest contrast computed tomography revealed a massive tumor in the left BD region, however, there were no findings for suspected malignancy. Needle biopsy did not yield histologically malignant cells in both breasts. Mammary interstitium was edematous, and capillary-like slit structures were observed. The stroma stained with alcian blue and destained with hyaluronidase treatment. Since the stroma tested positive for vimentin, calponin, and CD34 and negative for CD31, the patient was diagnosed as (PASH). Because both breasts had similar diagnosis based on histopathologic findings, bilateral mastectomy was performed. Details about the origin of bilateral PASH are unknown but it may be related to the development of rheumatoid arthritis. Additionally, systemic autoimmune diseases like rheumatism may be the reason for repeated contraction and enlargement of PASH.
