Male breast atypical ductal hyperplasia (ADH): clinicopathological insights from a rare cohort

Aims Atypical ductal hyperplasia (ADH) in male breast tissue is a rare condition with limited understanding. We aimed to elucidate the clinicopathological characteristics of ADH in male patients, focusing on its prevalence, presentation, and associated factors. Methods and Results We analysed 40 cases of ADH from 1626 male breast cases encountered between 2013 and 2023. Clinicopathological data were reviewed to identify key features and trends. The mean age of the patients in our cohort was 43 years. ADH was mainly discovered incidentally during the workup for gynecomastia in 85% (34/40) of cases. Only two cases, 5% (2/40), initially presented as a palpable mass; one was pure ADH and the other one an ADH with intraductal papilloma (IDP). Nipple discharge was the initial presentation in 7.5% (3/40) of cases, all of which were associated with IDP. Additionally, 5% (2/40) of cases were identified due to calcifications on imaging. Excision was the initial diagnostic procedure in 77.5% (31/40) of cases, and core needle biopsy (CNB) in 22.5% (9/40). In most patients 70% (28/40) had unilateral disease, while 84.4% (27/32) exhibited multifocal lesions, and 90.6% (29/32) showed cribriform architectural patterns. Notably, 77.3% (17/22) of patients had a history of medications linked to gynecomastia. During follow‐up (9 months to 26 years), two patients developed ductal carcinoma in situ (DCIS). Conclusion ADH in male patients primarily presents incidentally alongside gynecomastia. Multifocality and cribriform patterns are common histological features. The association with medication‐induced gynecomastia and the potential progression to DCIS highlight the clinical significance of ADH in males.