Lymphomas in Ile-Ife, Nigeria: Immunohistochemical Characterization and Detection of Epstein-Barr virus Encoded RNA.

Abstract

The proper histopathological characterization of malignant lymphomas requires the use of immunohistochemistry along with other molecular pathology techniques. Malignant lymphomas histologically diagnosed in our hospital were reclassified according to the WHO scheme using immunohistochemistry while in-situ hybridization was performed for the detection of Epstein-Barr virus encoded RNA. There were 83 cases of lymphoma. The male to female ratio was 1.9:1 while the overall mean age was 41.7 years. Non-Hodgkin lymphomas (NHL) constituted about 79.5% of cases. The majority of cases (98.8%) were B-cell lymphomas. Nine subtypes of lymphomas were identified with diffuse large B-cell lymphomas (56.4% of which were of the germinal centre type) constituting the largest group (47.0%). Intermediate and high grade subtypes were more common. The majority of cases (72.3%) were nodal lymphomas with cervical lymph node being the commonest site (48.2%). Only classical Hodgkin lymphoma (HL) (20.5%) was seen of which the mixed cellularity subtype was the most common. Epstein Barr virus (EBV) encoded ribonucleic acid was detected in 7 cases (8.4%) including 4 cases of HL, 2 cases of Burkitt lymphoma and the only case of plasmablastic lymphoma. About five cases were reclassified as non-lymphoid malignant lesions. Immunohistochemistry is vital to the proper classification of lymphomas even in a resource poor environment. Although nine subtypes of lymphomas were identified, diffuse large B-cell lymphomas formed the largest single group. Epstein-Barr virus probably plays an important role in lymphomatogenesis in this environment. A larger multicentre study is required to prove this.