Our patient was a 50 year old female with a history of HIV on HAART (Highly Active Antiretroviral Therapy), who came in to our center for routine breast cancer screening. She had a significant family history of breast cancer in her sister, maternal grandmother and her aunt. Her last mammography was two years prior which only showed benign calcifications in both breasts and an enlarged benign-appearing lymph node, hence a BI-RAD 2 (Breast Imaging Reporting Data) designation was given. On the day of presentation, the patient was asymptomatic. She denied any B-symptoms (night sweats, fever, etc) or bone pain. Digital screening mammography was obtained which showed a new circumscribed nodule in the right upper quadrant measuring 2.3 cm, multiple circumscribed benign-appearing lymph nodes in each breast and bilateral axillary lymphadenopathy (fig. ​(fig.1).1). A BI-RAD 0 (incomplete) designation was given. Exaggerated right CC view showed multiple circumscribed nodules in the lateral right breast with the largest nodule measuring about 2 cm (fig. ​(fig.2).2). Sonographic evaluation was performed on the upper outer aspect of the right breast which showed an echo-lucent mass (fig. ​(fig.3).3). Adjacent to that mass was another 9 mm hypoechoic area and an area in the 10 o'clock position consisting of clustered microcysts measuring 6 × 4 × 7 mm (fig. ​(fig.4).4). A BI-RAD code of 4 was given for the suspicious lesions and fine-needle cyst aspiration was ordered. During the procedure, core biopsy was initiated because the mass was solid. Pathology results from the breast biopsy showed an aggressive high-grade B-cell lymphoma with positive immunostaining for CD20, CD10 and Bcl-6 (fig. ​(fig.5).5). The Ki-67 proliferation index was approximately 80%. PET/CT scan was ordered for staging which showed focal FDG accumulation in the right breast mass with ipsilateral axillary adenopathy (fig. ​(fig.66 and ​and7).7). Right breast lumpectomy with right axillary lymph node biopsy was performed and the patient was started on systemic chemotherapy.

Breast lymphomas have been reported in various publications as a rare cause of a breast mass. Most breast lymphomas are of the Non-Hodgkins type with secondary breast lymphoma being much more common than the primary type. Primary lymphoma of the breast – which is lymphoma confined to the breast and the ipsilateral lymph nodes – accounts for less than 0.7% of all Non-Hodgkins lymphomas (NHL) [1,2]. It has been reported in recent papers that the rare occurrence of extranodal lymphoma of the breast is due to the relative paucity of intramammary lymph nodes [3].