Pediatric B-cell Lymphoma, Unclassifiable, With Intermediate Features Between Those of Diffuse Large B-cell Lymphoma and Burkitt Lymphoma: A Report of Two Cases

B-cell lymphoma, unclassifiable, with intermediate features between those of diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL; intermediate BL/DLBCL) commonly exhibits a morphology similar to that of typical BL and an atypical immunophenotype such as diffuse and moderate-to-strong BCL2 positivity and/or a Ki67 proliferation index <90%. Alternatively, the tumor cells exhibit greater variations in nuclear size and contouring than would be considered acceptable for BL [1, 2]. Intermediate BL/DLBCL is most commonly observed in adults [3-5]. Among pediatric populations, to date, the English literature only includes reports of one case of intermediate BL/DLBCL in a 2-yr-old Korean boy and eight cases in Chinese children [6, 7]. Here, we report two additional cases that represent the first report from a western population.