Pigmented epidermotropic metastasis of a breast carcinoma.

Mammary and extramammary Paget's disease is believed to remain non-pigmented, in contrast to superficial pagetoid melanoma; the same holds true for epidermotropic metastases of breast carcinoma. We recently had the opportunity to observe intensively pigmented epidermotropic metastasis of breast carcinoma, with dispersion of melanocytes in the dermal infiltrate. Similar observations, although exceedingly rare, have been reported: melanocytes 'may' pullulate within the dermo-epidermal foci of malignant epithelial cells. The final diagnosis relies on very careful analysis and, as far as possible, on immunohistological techniques.