Immunohistochemical Profile of Hodgkin and Non-Hodgkin Lymphoma.

Objective: To analyze the frequencies of histological types of lymphoma, diagnosed with complete immunohistochemical profile in younger and older age group.

Study Design: Cross-sectional analytical study.

Place And Duration Of Study: Dow Diagnostic Research and Reference Laboratory, Dow University of Health Sciences, Karachi, from January 2009 to September 2013.

Methodology: Consecutive cases of lymphomas, which were diagnosed using immunohistochemistry, were analyzed according to WHO classification. Frequency and percentages for different types of lymphomas were calculated. Hodgkin and non-Hodgkin lymphomas characteristics in two age groups of less than and more than 40 years were compared, applying chi-square test.

Results: Out of the 318 cases, 79 (25%) were Hodgkin Lymphomas (HL) and 239 (75%) were Non-Hodgkin Lymphomas (NHL). Mixed Cellularity Hodgkin Lymphoma (MCHL) was the commonest (n=48). Amongst the NHL, 215 (89.95%) were B cell lymphomas and 24 (10.05%) were T-cell lymphomas. Diffuse Large B-Cell Lymphoma (DLBCL) was the commonest lymphoma (n=165, 69.95% of NHL). Anaplastic T-Cell Lymphoma (ALCL, n=10) was the commonest T-cell lymphoma. The frequency of HLwas significantly higher in the younger age group and that of NHLwas higher in the older age group (p < 0.001). Primary lymph node involvement was reported in 175 (55%) and cervical lymph node was the most frequent site. Extra nodal involvement was seen in 93 (29%) of all cases and was reported in 87 (36.4%) of NHLand 6 (7.5%) of HL. The most common extra nodal site was the gastrointestinal tract.

Conclusion: Hodgkin lymphoma comprises 25% and non-Hodgkin lymphoma comprises 75% of all lymphomas. Both occur in younger age groups than reported in the West. B-cell NHLis three times more common than T-cell lymphoma. DLBCLis the most frequent lymphoma. ALCLis the most common T-cell, and mixed cellularity is the most common Hodgkin lymphoma.