Small B cell Non-Hodgkins Lymphoma in Pakistan.

OBJECTIVE To study the pattern of small B cell lymphomas in Pakistan. METHODS This descriptive study was carried out at the Aga Khan University Hospital pathology department including 1721 cases of Non-Hodgkins Lymphoma (NHL) diagnosed during a period of five years (1998-2002) and classified according to REAL/WHO classification. The antibodies used included Leukocyte Common Antigen (LCA), Pan B (CD20, CD79a), Pan T (UCHL-1), Bcl 2, Mib 1(Ki 67) and Cyclin D1 (Dako, Denmark). RESULTS Out of the 1721 NHL cases, only 140 (8.1%) could be categorized as small B-cell NHL. The study group comprised small lymphocytic lymphoma/chronic lymphocytic leukemia (58 cases; 41.4%) followed by follicular lymphoma (46 cases; 32.9%), mantle cell lymphoma (15 cases; 10.7%), extra nodal marginal zone B cell lymphoma of MALT type (15 cases; 10.7%), lymphoplasmacytic lymphoma (5 cases; 3.6%) and splenic marginal zone B-cell lymphoma (1 case; 0.7%). No case of nodal marginal zone lymphoma was diagnosed. The age ranged from 18 to 98 years with a mean and median of 54.64 and 58.50 years respectively. Small B-cell NHL was more common in males; with male to female ratio of 2.1. Majority of the small B-cell NHL were nodal at presentation with a nodal to extranodal ratio of 3.4. CONCLUSION It is concluded that the frequency of these small B-cell NHL is very low in our population in contrast to the western literature. Further studies based on epidemiologic and etiological factors are required to look into this marked difference of occurrence of these indolent lymphomas.