Gynecomastoid and pseudoangiomatous stromal hyperplasia: a case report with literature review

Abstract Gynecomastoid hyperplasia (GMH) is a rare benign breast lesion that histologically resembles male gynecomastia and typically presents as a palpable breast mass in young women. Its coexistence with pseudoangiomatous stromal hyperplasia (PASH) has been noted but rarely described in detail. We report the case of a 16-year-old female who presented with a four-month history of unilateral, left-sided, clear serous nipple discharge without a palpable mass or other clinical abnormalities. Ultrasound demonstrated an ectatic duct containing two intraductal soft-tissue lesions (BI-RADS 3), raising suspicion for intraductal papilloma. Vacuum-assisted excisional biopsy revealed dense collagenized PASH-type stroma with benign mildly hyperplastic ductal epithelium and absence of terminal duct-lobular units, confirming the diagnosis of GMH associated with PASH. The patient’s symptoms had resolved at the four-month follow-up, after which she was lost to follow-up. A review of the literature showed that GMH most commonly affects women between the second and sixth decades of life, usually presenting as a palpable breast mass, with imaging findings ranging from benign to suspicious for malignancy. Histologically, it is characterized by ductal hyperplasia, periductal fibrosis or edema, and absence of lobules. The coexistence of GMH and PASH has been reported only briefly, without detailed clinicopathological description. This case expands the clinical spectrum of GMH by demonstrating that it may occur in adolescents and present solely with nipple discharge. GMH associated with PASH should therefore be considered in the differential diagnosis of unilateral nipple discharge, particularly in young patients.