CLL-140: Chronic Lymphocytic Leukemia Presenting as a Solitary Breast Mass

Abstract

An 80-year-old woman with a past medical history of hypertension and no prior history of malignancy underwent a screening mammogram followed by a breast ultrasound that showed a right breast mass. She remained asymptomatic. The physical exam did not reveal any palpable lymphadenopathy nor hepatosplenomegaly. Peripheral blood smear showed absolute lymphocytosis of 69% with a normal total white blood cell count of 8.1 without dysplastic cells, blasts, anemia, or thrombocytopenia. Breast ultrasound showed an irregular hypoechoic mass measuring 0.7 x 0.5 x 0.5 cm. Subsequent US-guided core biopsy showed non-Hodgkin B-cell lymphoma positive for cluster designation (CD)20 and CD5. Bone marrow aspirate and core biopsy revealed clusters of small-to-medium atypical lymphocytes positive for CD20, CD79a (weak), with a co-expression of CD5 (strong) and CD23CD138, findings that are compatible with Small Lymphocytic Lymphoma (SLL)/Chronic Lymphocytic Leukemia (CLL). Positron Emission Tomography scan showed an uptake within the right breast only. She is being managed with observation and close follow-up. Breast lymphoma (BL) represents around 0.5% of malignant breast neoplasms. Diffuse Large B-Cell Lymphoma (DLBCL) and follicular lymphoma are the predominant subtypes. SLL and CLL are subtypes of non-Hodgkin lymphoma originating from a B-cell lineage. While there have been reported cases of CLL and SLL manifesting as BL, the incidence still is very low and limited to case reports. Moreover, they have been reported to be found concomitantly with breast carcinoma. Most BL are asymptomatic when found incidentally on screening imaging, as in our patient. A hypoechoic round mass is the most common reported appearance. There are no current established guidelines for the treatment of BL. In our patient, we followed the recommendations for managing CLL. Not all breast masses are adenocarcinoma. It is critical to keep in mind the differential diagnosis lymphoproliferative disorders, melanoma, lung cancer, and gynecological malignancies.