Pattern of malignant lymphomas in Rwanda.

The pattern of 115 cases of malignant lymphomas diagnosed in the years 1979-1987 is presented using the updated Kiel's classification for non Hodgkin's lymphomas and after application of monoclonal antibodies L 26 and UCHL1 for the identification of B and T lymphocytes. Ninety-six cases (83.5%) were non Hodgkin's lymphomas and 19 cases (16.5%) Hodgkin's disease. Among non Hodgkin's lymphomas, B-cell lymphomas were predominant with a total number of 91 cases (94.8%). An analysis of B-cell lymphomas showed the following relevant features: a high frequency of lymphoplasmacytic/oid immunocytoma, a low frequency of Burkitt's lymphoma with a predominance of abdominal localisations, a high frequency of extranodal lymphomas (47.3%) and high grade lymphomas (48.4%); a 65% increase in high grade and extranodal lymphomas and a 76% increase in Burkitt's lymphomas and immunoblastic lymphomas in the period 1984-87 compared to the period 1979-83. For T-cell lymphomas, relevant features were the presence of one case of pleomorphic T-large cell lymphoma or adult T-cell leukemia-lymphoma and the fact that four out of five cases were large cell (high grade) lymphomas. More than 50% (57.9%) of Hodgkin's disease were of mixed cellularity type, only 15.8% being of nodular sclerosing type. The disease seemed to affect adolescents and young adults, more than 80% (83.3%) being aged 15-40 years. These features are compared to those observed by other authors and possible pathogenetic mechanisms are discussed.