Lymphoepithelioma-like carcinoma of the breast: report of a case mimicking lymphoma.

Only 10 cases of lymphoepithelioma-like carcinoma of the breast have been reported in the literature. This report adds one more case to the published literature. A 62-year-old woman presented with a mass in her left breast on physical examination. The mammographic images showed a 3.0 cm, poorly defined mass in the upper outer quadrant. A biopsy was recommended. The gross specimen consisted of a 5 cm portion of breast parenchyma with no discrete tumor. On microscopic examination, the tumor was composed of sheets of epithelioid cells arranged as single cells or in cords partially obscured by a dense lymphocytic infiltrate. The epitheliod cells extensively expressed cytokeratin stain, but did not express E-cadherin. The lymphoid cells expressed L26 stain in the germinal centers, and CD3 stain in the T lymphocytes surrounding the germinal centers and in between tumor cells. In situ hybridization showed no evidence of Epstein-Barr virus infection in the tumor cells. An overall review of 11 cases shows that the disease is usually seen in older patients. In situ and invasive lobular component was reported in 36% of the cases. Eight of 11 were negative for E-cadherin, 36% were estrogen receptor-positive, 18% were progesterone receptor-positive, and all of them were HER2/neu negative. None of the reported cases have been associated with Epstein-Barr virus infection. Only two of the cases showed lymph node metastasis, and long-term follow-up in one of them showed good prognosis. In summary, lymphoepithelioma-like carcinoma of the breast is a tumor with a good prognosis that should be considered as a possible diagnosis in breast tumors with an intense lymphocytic infiltrate.