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

Abstract

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 (PD). Differential diagnosis should be established with entities with a similar presentation, such as pigmented mammary PD 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.

Poorly differentiated cutaneous apocrine carcinomas: histopathological clues and immunohistochemical analysis for the diagnosis of this unusual neoplasm

“…This histopathological clue can be focal, often requiring submission of the entire specimen for histological inspection. While metastatic visceral adenocarcinomas to the skin can be epidermotrophic, this is an unusual event 23–25 . In such cases, attention to evaluate acrosyringium involvement is key as cases of epidermotrophic metastasis do not display ductal invasion.…”

“…While metastatic visceral adenocarcinomas to the skin can be epidermotrophic, this is an unusual event. 23 , 24 , 25 In such cases, attention to evaluate acrosyringium involvement is key as cases of epidermotrophic metastasis do not display ductal invasion. In addition, preservation of the myoepithelial cell layer would support the diagnosis of a primary cutaneous tumour rather than a metastasis.…”