Giant Pseudoangiomatous Stromal Hyperplasia Presenting as Bilateral Macromastia in an 11-Year-Old Female Patient: Emphasis on Pediatric Presentation and Literature Review

Pseudoangiomatous stromal hyperplasia (PASH) is a benign proliferative lesion of the breast stroma, most often encountered in premenopausal women as a small unilateral nodule. Occurrence in children and adolescents is exceedingly rare, particularly in the setting of diffuse involvement causing bilateral macromastia. Here, we present the largest documented instance of PASH (in size and weight) in an 11-year-old premenarchal female patient with rapidly progressive, symptomatic bilateral, diffuse breast enlargement, ultimately requiring bilateral subtotal mastectomy with free nipple grafting. Bilateral tumors measured 39.1 cm and 29.2 cm, with resection weights of 10.2 kg and 5.2 kg. In addition, we reviewed all published literature on school-aged children with PASH (ages 6-12, n = 12) and compared them with nine large adult series (n ≈ 1072). Pediatric lesions showed significantly higher rates of bilaterality (50% vs <1%), diffuse/macromastic growth (58% vs <1%), larger mean size (18.3 cm vs 4-5 cm), and greater need for mastectomy (42% vs 1.5%). Our observations from clinical presentations in the literature and our from patient demonstrate that pediatric PASH has the potential to present as rapid, massive bilateral breast enlargement, suggesting that pediatric PASH is not merely a smaller form of the adult disease but a distinct clinical entity requiring age-appropriate management.