A case of acute onset gigantomastia in a 20-year-old woman

Gigantomastia is an abnormal and rare breast condition characterized by excessive breast tissue growth that can result in physical and psychosocial debilitation. While the etiology is not fully understood, it is postulated that abnormal endogenous hormone stimulation plays a contributory role and often requires mastectomy for definitive treatment. Proliferation of all elements is commonly observed, including glands, ducts, stroma, fat, vessels and skin. Pseudoangiomatous stromal hyperplasia (PASH) is an additional benign breast disease defined microscopically by proliferation of mammary stroma. PASH often clinically presents as an incidental finding while evaluating other benign or malignant lesions, or less commonly as a palpable, well-circumscribed breast mass. Uncommon cases have been reported in which PASH presents as a bilateral, diffuse process. In this case presentation, we report a rare case of a 20-year-old woman presenting with acute onset gigantomastia most likely due to diffuse PASH. •Gigantomastia is a rare condition of the breast characterized by excessive breast tissue growth.•The ddx for gigantomastia includes fibroepithelial lesions and PASH. Malignant carcinoma must first be excluded.•PASH may present as an incidental finding on imaging, a palpable lump, and rarely bilateral diffuse breast enlargement.