Reflectance Confocal Microscopy for Diagnosis of Mammary Paget's Disease

Mammary Paget’s disease (MPD) is an uncommon intra-epidermal adenocarcinoma of the nipple-areola complex, occurring in 1–5% of all breast carcinomas (1). MPD is difficult to diagnose clinically as it mimics a variety of both inflammatory and neoplastic skin diseases (2). Pigmented mammary Paget’s disease (PMPD) corresponds to an even less common variant, frequently simulating other pigmented lesions of the nipple, including melanoma (3–5). According to the epidermotropic theory, Paget cells (PCs) originate from cancer cells that migrate via the lactiferous ducts along the basal membrane, to invade the epidermis of the nipple and areola (6, 7). Considering its intra-epidermal spreading, PCs are therefore potentially demonstrable using non-invasive diagnostic techniques with near-cellular resolution, such as reflectance confocal microscopy (RCM) (8). The aim of this study was retrospectively to describe the RCM features of 5 cases of MPD, with dermoscopic and histopathological correlation.