Introduction-
Primary Breast Non-Hodgkin’s Lymphoma (PBNHL) are very rare breast
malignancies, accounting for 2.2% of all extra nodal lymphomas and for 0.04% to 0.5% of malignant breast neoplasms (7). Primary breast lymphomas are mainly diffuse large B-cell non-Hodgkin lymphoma (B-DLC-NHL and T-Cell, MALT and Burkett’s being extremely uncommon (4,5,6). Those of T-cell origin have been associated with breast implants (17). Although exact etiology is unknown, chronic infection, immune suppression, environmental exposures to ionizing radiation and hereditary traits are the proposed risk factors (8,9)
The rarity of PBL may be related to the small amount of lymphoid tissue present in the breast (2,3) as compared to the gut or lung, in which the occurrence of primary lymphomas is much more frequent. Mostly unilateral involvement has been reported but the lesions may even be bilateral. Bilateral synchronous breast lymphoma occurs in 10% of patients, and contralateral metachronous disease occurs in up to 15%. Bilateral disease is a poor prognostic factor with higher rates of CNS metastasis.
The Ann Arbor classification of PBNHL also has been defined-
Stage 1- tumor limited to the breast
Stage 2- Tumor confined to the breast with palpable ipsilateral axillary lymphadenopathy.
Stage 3 - Tumor confined to the breast with metastasis on both sides of the diaphragm
Stage 4 - Tumor limited to the breast with spread to extra nodal lymphoid tissue.