Clinical and radiologic characteristics of ruptured epidermal inclusion cysts in the nipple and subareolar regions: A report of two cases.

Epidermal inclusion cysts (EICs) in the breast, particularly in the nipple and subareolar regions, are rare entities that pose significant diagnostic challenges and management dilemmas in clinical practice. This study retrospectively analyzes two case reports of women presenting with EICs located in these unusual breast areas. The subjects included a 35-year-old female with congested nipple symptoms and bilateral mastodynia, and a 58-year-old female with a palpable right breast nodule. Diagnostic efforts involved magnetic resonance imaging (MRI), sonography, and mammography, which highlighted the cysts' onion-like asymmetry and heterogeneous characteristics with posterior acoustic enhancement. Despite detailed imaging, distinguishing these cysts from malignancies or typical abscesses proved difficult. Both cases experienced spontaneous cyst rupture with subsequent resolution following antibiotic therapy. A literature review confirmed the rarity of such cases, emphasizing the importance of recognizing EICs to avoid unnecessary surgical interventions. These findings underscore the need for heightened clinical awareness and detailed imaging to accurately diagnose and manage EICs in atypical breast locations, and call for further research to explore their etiology and optimal treatment strategies.