Paget's disease of the male breast in the 21st century: A systematic review.

Paget's disease of the breast is characterized by eczematous changes of the nipple-areolar complex and is associated with an underlying in situ or invasive breast carcinoma in most cases. Histologically, Paget's disease is identified by epithelial cells with abundant basophilic or amphophilic, finely granular cytoplasm with a large, centrally situated nucleus, most abundant in the lower epidermal layers. Due to the rarity of the condition among breast cancers, compounded by the rarity of breast cancer in men, understanding of the disease's presentation, course, and optimal treatment in men is largely derived from case reports and extrapolation of findings from studies in female patients. Paget's disease must be differentiated from other conditions including eczema, Bowen's disease, squamous cell carcinoma, and melanoma. Recognition of Paget's disease clinically and pathologically is critical as the superficial lesion may be the only sign of an underlying ductal carcinoma and its presence may be of prognostic significance. This article provides an update on cases of Paget's disease of the breast in men reported in the published literature together with a comprehensive analysis of the National Cancer Institute's Surveillance, Epidemiology, and End Results Data, 1973-2012. Current understanding and management of the disease in the context of male patients is reviewed. However, additional research is required to further understand the overall pathogenesis and molecular profile of Paget's disease to provide improved insight for personalized, precision-based therapeutic options.