High‐Grade B‐Cell Lymphoma With 11q Aberration in Africa: A Differential Diagnosis in Cases With Features of Endemic Burkitt Lymphoma

ABSTRACT Fifty years ago, Zech et al. in this journal described for the first time the t(8;14) as a recurrent chromosomal aberration in Burkitt lymphoma (BL). Nevertheless, in regions where BL is not endemic, a subset of lymphomas with features of BL lacks the t(8;14)/ IG :: MYC and instead represents high‐grade B‐cell lymphoma with 11q aberration (HGBCL,11q). As Zech et al. already noted the cell line BJAB to be an exception as BL from a 5‐year Kenyan girl in being EBV‐negative, lacking the t(8;14) but showing a chromosome 11 aberration, we here revisited and updated the molecular features of BJAB. Genetic analyses confirmed its East African origin and absence of IG :: MYC but unraveled complex 11q aberrations, including gains in 11q14.1‐q23.1, loss of 11q23.2qter, and, notably, a nonreciprocal 5′KMT2A :: CLTC3′ ‐fusion. The mutational landscape contained genes typically mutated in mature B‐cell lymphomas but no driver genes restricted to BL. Therefore, we hypothesize that BJAB derives from an African HGBCL,11q. To investigate the presence of this entity in East Africa, we analyzed 24 cases with Burkitt or high‐grade morphology diagnosed at Kenyatta National Hospital. Twenty cases fulfilled the morphological and immunophenotypical criteria for the diagnosis of BLs (11 EBV‐positive, 9 EBV‐negative). Genetic testing in these cases identified one EBV‐negative case (20 years) as MYC‐nonrearranged but displaying the typical 11q pattern, thus representing HGBCL,11q. Among the four HGBCL with intermediate features, two showed gains in 11q including the region typically deleted in HGBCL,11q. Our findings establish HGBCL,11q as a relevant differential molecular diagnosis to Burkitt lymphoma in sub‐Saharan Africa.