The differential diagnosis of a breast mass in an HIV-infected patient is broad. We report a case of HIV-associated intramammary lymphadenopathy that manifested itself as a painful solitary breast mass best demonstrated by ultrasound imaging. Fine-needle aspiration (FNA), ultrasound-guided core needle biopsy, and subsequent excisional biopsy demonstrated an intramammary lymph node with reactive changes typical of acute HIV-associated lymphadenopathy. Intramammary lymphadenopathy, an otherwise under-reported entity, should be included in the differential diagnosis of a breast mass in an HIV-positive patient. FNA sampling alone can be adequate in such low suspicion breast lesions that appear benign on clinical and imaging evaluations, provided that sufficient cellular material is procured for ancillary studies to exclude infection and malignancy.