A monolateral pigmented lesion of the nipple

Abstract

Pigmented mammary Paget's disease is a very rare variant of mammary Paget's disease linked to an underlying carcinoma in almost all cases. We present the case of a 62-year-old female patient who came to our attention for the evaluation of a monolateral asymptomatic pigmented lesion of the right nipple, which turned out to be a pigmented mammary Paget's disease unassociated to an underlying malignancy - an extremely rare entity only anecdotally reported in literature. The two main peculiarities of our patient's lesion, the importance of immunohistochemistry in the differential diagnosis and the theories on its pathogenesis are discussed. Further studies are necessary to establish the best treatment options. Click here for the corresponding questions to this CME article.

Figure 1

(a) A monolateral poorly demarcated pigmented lesion located at the upper outer quadrant of the right nipple–areola complex. (b) Dermoscopy showed a pigmented lesion with a brownish, bluish and whitish hue distributed in an irregular globular and reticular pattern without clear demarcation from the surrounding skin.

Figure 2

(a) Substantial number of large atypical cells with clear eosinophilic cytoplasm and pleomorphic nuclei scattered throughout the epidermis. (b) Some of the cells had bland pigmentation due to melanin phagocytosis. In the dermis, a chronic inflammatory infiltrate with a discrete number of melanophages was visible. Haematoxylin and eosin, original magnification (a) × 200; (b) × 400. (c) Neoplastic infiltrate showing a strong positivity for CK7 on immunohistochemical staining (original magnification × 200).