Pigmented epidermotropic breast cancer metastases. A rare variant with a particularly unusual feature

Pigmented epidermotropic breast cancer metastases are a rarity, often clinically misdiagnosed as melanocytic lesions. Histopathologically, they show a dermal proliferation of neoplastic metastatic cells that extend to the overlying epidermis in a pattern identical to that seen in primary Paget disease. Differential diagnosis should be established with entities with a similar presentation, such as pigmented mammary Paget disease and malignant melanoma. Immunohistochemistry may be useful for this purpose. We present a new case of pigmented epidermotropic breast cancer metastases with a particularly unusual feature: the absence of dermal infiltration by neoplastic cells, thus considered as pure epidermotropic metastatic involvement. This article is protected by copyright. All rights reserved.