Abstract
Primary breast lymphoma (PBL) is a rare entity. It represents 0.4% of malignant breast lesions and 2% of extranodal lymphomas. A 23-year-old woman presented with a left breast lump followed by palpable left axillary lymphadenopathy. Fine-needle aspiration cytology (FNAC) and histopathology were diagnostic of non-Hodgkin lymphoma-large cell type. Immunohistochemistry was positive against leukocyte common antigen and CD20. Because PBLs are uncommon malignant lesions and they usually do not have characteristic clinical and imaging findings, FNAC may prove to be a simple, rapid, reliable, and cost-effective procedure for successful diagnosis of the PBL.