Non-Hodgkin's lymphoma presenting as breast masses: a series of 10 cases diagnosed on FNAC.

Primary breast lymphoma (PBL) is a rare disease, which comprises 0.04-0.53% of all primary malignant tumors of the breast. The most frequent histological subtype is diffuse large B-cell type (DLBCL) (40-70%). Differentiation of PBLs from other breast tumors such as poorly differentiated carcinomas and lobular carcinoma may at times be difficult on cytomorphology alone. An audit of breast lymphomas diagnosed on fine needle aspiration cytology (FNAC) over a period of 9 years (2001-2009) was performed. Ten cases were retrieved and the cytomorphology was reviewed along with immunochemistry (IHC), flow cytometry as well as histopathology, wherever available. The age of patients ranged from 17 to 83 years. Eight cases were diagnosed as non-Hodgkin's lymphoma, high-grade on FNAC. Histopathology was available in four of these cases and cell block was available in one case. Lymphoid cells were positive for leukocyte-common antigen (LCA) and CD20 and negative for CD3 in these cases. The same was confirmed by flow cytometry on aspirated material in one case. A diagnosis of DLBCL was offered in these five cases. One case was a low-grade NHL and another case was a young male, a known case of acute leukemia and had leukemic infiltration in the breast lump. We wish to emphasize the potential importance of FNAC in breast lymphoma and the same can be helpful to avoid unnecessary surgery in these cases. The differential diagnostic entities have been discussed. IHC and flow cytometry can be performed on the aspirated material and provide valuable information.