Male breast lymphoma is a rare extranodal lymphoma occupying the mammary gland, and it could be either primary or secondary. A 78-year-old man presented an enlargement of the right breast. He had no medical history of interest. On physical examination, a unilateral, painless breast lump was found, with no skin changes or nipple discharge. There was no palpable lymphadenopathy. Routine laboratory tests revealed leukocytosis and lymphocytosis. Excisional biopsy of the breast lesion revealed mammary tissue infiltration by chronic lymphocytic leukemia (CLL) with plasmacytoid features and immunoglobulin G∕kappa monotypic expression. To our knowledge, this is the first report of male breast involvement by CLL. Considering important the collection of clinicopathological data of all reported male breast lymphoma cases, a literature review is presented.