Immunophenotypic patterns of lymphomas in a tertiary hospital, lagos, Nigeria.

This study aims to classify the various types of lymphomas seen in our center by morphology and immunopenotyping using basic antibody panel. Materials and Methods: Using 3-5 member antibody panels in sequential batches as primary, secondary and tertiary antibodies selected from the list of available antibodies), immunohistochemical staining were done on 110 cases of formalin- fixed paraffin-embedded lymphoma tissue blocks from the archive. A prior microscopic assessment of the hematoxylin-eosin-stained sections of each tissue block was done. All cases were diagnosed and sub typed by their morphology and pattern of antigen immunoreactivity. Results ; of the 110 cases of lymphoma, non Hodgkin lymphoma (NHL) constituted 84.5 % (93 of 110 cases), while Hodgkin lymphoma (HL) was 15.5 % (17 of 110 cases). The B cell NHL was 65.5 % (71 of 110 cases) and T cell NHL was only 20 % (22 of 110 cases). Of the B cell NHL, Diffuse large B cell lymphoma (DLBL) constituted 45.1 % (32 of 71 cases), while Small lymphocytic lymphoma (SLL) and Follicular lymphoma (FL) were 21.1 % (15 of 71) and 10.0 % (7 of 71) respectively. Burkitt lymphoma (BL) was only 7.0 % (5 of 71); while 5 (7.0 %) and 3 (4.2 %) cases of Mantle cell lymphoma (MCL) and Mantle zone lymphoma (MZL) were seen respectively. Only 3 (4.2 %) and 1 (1.4 %) cases of MALTOMA and precursor B cell lymphoma were seen respectively. T / NK -cell lymphomas constituted 31 % (22/110) of all the lymphomas and 20 % of NHL and 36.4% (8/22) were extranodal. Peripheral T cell lymphoma (PTCL) constituted 45.5 % (10 of 22) of the T cell lymphomas. Precursor T cell lymphoma (pre TCL) constituted 22.7% (5 of 22), while 18.2% (4 of 22) and 13.6% (3 of 22) were cases of mycosis fungoides (MF) and anaplastic large cell lymphoma (ALCL) respectively The overall male: female ratio was 1.4:1 while the mean age for adult and childhood NHL were 46 and 9 years respectively. All the cases of lymphomas in our study could be diagnosed and classified using CD 20 or CD79a, CD5, CD 23, CYCLIN D1, CD 10, BCL6, and Ki - 67 for mature B cell lymphoma, including DLBCL. CD 15, CD30, CD45, pancytokeratin, EMA, ALK 1 are useful for cases with large cell morphology while CD 3, CD7, CD4, CD8, PD1, CD25, CD10, and CD23 are required for mature T cell lymphomas. A consideration for Acute lymphoma / leukemia will require in addition to B and T cell markers (CD3,CD79a), CD 34 and Tdt and differentiating between reactive and malignant lymphoproliferative lesions requires BCL 2, CD 43, CD56, and ALK -1. Conclusion : This study further underscored the importance of immunohistochemistry in diagnostic haematolymphoid oncology. Starting with the availability of at least 10 antibodies (CD20, CD 79a, CD5, CD10, BCL 6, Tdt / CD34, CD15, CD 30, ALK-1, CYCLID D1, Ki67, CD3, pancytokeratin) and good diagnostic skill, most of the tertiary hospitals in developing countries will be able to perform, to a large extent, meaningful diagnosis of most of the common lymphomas. The list can be expanded with time as demanded. More detailed studies will be necessary to find out the potential infective aetiological factors in the development of high grade B-cell lymphomas in the environment.