Dermoscopic features of mammary Paget's disease: a retrospective case-control study by the International Dermoscopy Society

Background Mammary Paget's disease (MPD) is a rare intraepidermal adenocarcinoma of the nipple-areola complex, associated with an underlying breast cancer in approximately 90% of cases. Delayed diagnosis of MPD is common. Its dermoscopic features have been ill defined in the literature. Objectives To determine the clinical and dermoscopic features of MPD versus other dermatologic entities that involve nipple and areola. Methods Members of the IDS were invited to submit any case of histologically confirmed MPD, as well as other benign and malignant dermatoses that involve the nipple and areola complex. A standardized evaluation of the dermoscopic images was performed and the results were statistically analyzed. Results Sixty-five lesions were included in the study, 22 (33.8%) of them MPD and 43 (66.2%) controls. The most frequent dermoscopic criteria of MPD were white scales (86.4%) and pink structureless areas (81.8%), followed by dotted vessels (72.7%), erosion/ulceration (68.2%) and white shiny lines (63.6%). The multivariate analysis showed that white scales and pink structureless areas were significant predictors of MPD, posing a 68-fold and a 31-fold probability of MPD, respectively. Split of the population into pigmented and non-pigmented lesions showed that in pigmented MPD, pink structureless areas, white lines and grey granules and dots are positive predictors of the disease. Among non-pigmented lesions, pink structureless areas, white lines, erosion/ulceration and white scales served as predictors of MPD. Conclusions The most frequent profile of an individual with MPD is an elderly female with unilateral, asymptomatic, erythematous plaque of the nipple, dermoscopically displaying pink structureless areas, fine white scales, dotted and a few short linear vessels. In case of pigmentation we may also observe brown structureless areas and pigmented granules. Limitations Small sample size, retrospective design.