Two cancers in one: breast carcinoma with underlying melanoma.

A 61-year-old woman presented with a diagnosis of metastatic invasive lobular carcinoma of the right breast, and after treatment it had regressed or was stable except for a scalp nodule. When biopsied, the outer edges of the scalp lesion had findings consistent with breast carcinoma; however, the bulk of the tumor's pathology was consistent with melanoma. It appeared that most of the tumor was a highly vascularized melanoma with lobular breast carcinoma noted at its edges.