Male Breast Adenoid Cystic Carcinoma – A Narrative Review of a Rare Disorder

Background: Adenoid cystic carcinoma (ACC) is primarily a disease of the salivary glands and is exceptionally rare. Due to its rarity, there is no established consensus or recognised guidelines for management. This review aims to synthesise existing literature to improve clinical awareness and knowledge of male breast ACC (MB-ACC). Methods: A comprehensive literature search was conducted across PubMed/MEDLINE, Scopus, and Google Scholar for cases of MB-ACC published between 1969 and 2025. Inclusion criteria focused on peer-reviewed case reports providing clinical, histopathological, and immunohistochemical data. Approximately 20 cases were identified and analysed. Results: MB-ACC often presents as a slow-growing, subareolar mass, with a median age of onset (41.5 years) younger than typical male breast cancer. Diagnosis is confirmed via histopathology showing cribriform, tubular, or solid patterns with a double-layered cell structure. Most tumours are triple-negative (ER-/PR-/HER2-), though they paradoxically exhibit an indolent clinical course and favourable long-term prognosis compared with other triple-negative cancers. Management is primarily surgical, with modified radical mastectomy being the most frequently reported procedure. Conclusion: Although MB-ACC shares histological features with aggressive basal-like carcinomas, it carries a favourable prognosis. Early diagnosis through awareness is essential to avoid advanced presentation. Given the potential for late recurrence, long-term follow-up is recommended.