Small Lymphocytic Lymphoma Presenting as a Breast Lump: A Rare Presentation of Non-Hodgkin's Lymphoma

Approximately one-fourth of non-Hodgkin's lymphomas (NHLs) present with an extranodal origin. Primary and secondary involvements of the breast by lymphoma are rare because of the paucity of lymphoid tissue in the breast. Primary breast small lymphocytic lymphoma (SLL) typically presents as a manifestation of widespread chronic lymphocytic leukemia (CLL). A 58-year-old female presented to our clinic with a palpable breast mass. She had no cytopenias and her absolute peripheral B lymphocyte count was less than 5000/microL. The mass was biopsied and histology with immunohistochemistry showed neoplastic cells positive for CD23 and CD5 confirming the diagnosis of small B cell lymphocytic lymphoma of the breast. Further imaging revealed extensive mediastinal and retroperitoneal lymphadenopathy. Histopathology of bone marrow biopsy revealed diffuse infiltration with SLL. The patient was treated with six cycles of fludarabine, cyclophosphamide and rituximab (FCR) with excellent clinical response. To our knowledge, this is the first case of SLL infiltration of the breast without CLL treated successfully with FCR.