Fungating mass on the breast of a male patient.

Breast cancer is one of the most common malignancies that can lead to cutaneous metastasis. Dermatopathologists often play an important role in the diagnosis of breast cancer metastasis to the skin. Rarely, dermatopathologists render a histopathologic diagnosis of primary breast cancer. We discuss a 51-year-old man with metastatic breast adenocarcinoma who presented after admission to the intensive care unit in the setting of altered mental status and critical anemia. Examination revealed a 14cmx12cm ulcerated, fungating tumor occupying the left breast. A four mm punch biopsy from the mass showed cords of atypical cells infiltrating the mid-to-deep dermis positive for CK7, GATA3, ER and PR. CK20, P40, p63, and TTF1 stains were negative. HER2/NEU immunoperoxidase stain was negative. CA15-3 was elevated at 75U/ml. Taken together, he was diagnosed with primary left breast ductal adenocarcinoma, grade two with subsequent visceral metastases to the bones, lymph nodes, and lungs. Although male breast cancer makes up less than 1% of all breast cancers, its incidence has been increasing worldwide. Recognition of the unique clinical and histologic findings of primary breast carcinoma is important to avoid delay in the diagnosis and initiation of appropriate treatment.