Distinct pattern of lymphoid neoplasms characterizations according to the WHO classification (2016) and prevalence of associated Epstein-Barr virus infection in Nigeria population.

The present study aimed to classify lymphoid neoplasms according to the latest World Health Organization (WHO) classification and outlining the distribution in Nigeria of different entities. Additionally, the study describes the prevalence of lymphoid neoplasms associated with Epstein-Barr virus (EBV) infection in the Nigerian population. We collected 152 formalin-fixed paraffin-embedded (FFPE) tissues diagnosed as lymphoma from 2008 to 2018, coming from three different institutions located within three geopolitical zone in Nigeria. These institutions included the University College Hospital (UCH), Ibadan, Oyo State, the Enugu State University of Science and Technology Teaching Hospital (ESUTH), Enugu, Enugu State, and the Meena Histopathology and Cytology Laboratory (MHCL), Jos, Plateau State. From the total 152 cases retrieved, 50 were excluded due to insufficient tissue materials or inconclusive antigen reactivity. We confirmed 66 (64.7%) cases as lymphomas out of the remaining 102 FFPE with a male to female ratio of 2:1 and a mean age of 44.4 years. Ten entities were identified, and of these, chronic lymphocytic leukemia (CLL) was the most prevalent category (34.8%). For the diffuse large B-cell lymphomas not otherwise specified (DLBCL, NOS), the germinal centre B–cell type was the most common (71.4%). Ten lymphoma cases (15.2%) were positive for Epstein-Barr virus (EBV), most of which were Hodgkin lymphoma (HL). CLL was common in the Hausa ethnic group, HL in the Yoruba ethnic group, while the Igbo ethnic group had an equal distribution of CLL, HL, and DLBCL diagnosis. Although the distribution of lymphomas in Nigeria shares some similarities with those of other countries, we described distinct features of some subtypes of lymphomas. Also, the study underscores the need for a more precise diagnosis and classification of lymphoid neoplasms in Nigeria using the latest WHO classification.