Lymphoepithelioma-like carcinoma of the breast with associated sclerosing lymphocytic lobulitis.

The purpose of this article is to highlight an unusual form of breast carcinoma and discuss its differential diagnosis. A 50-year-old woman underwent wide local excision of a breast lump. Microscopic examination revealed features of a lymphoepithelioma-like carcinoma. Individual tumor cells were present within an abundant lymphoid stroma. Immunohistochemistry revealed the epithelial nature of the cells and excluded a diagnosis of lymphoma. In addition, surrounding nontumorous breast tissue displayed the histologic features of sclerosing lymphocytic lobulitis or lymphocytic mastopathy. This is the second report of a lymphoepithelioma-like carcinoma of the breast, but to the best of our knowledge, it is the first description of coexistent sclerosing lymphocytic lobulitis.