"In situ" MYC rearrangement and amplification as a secondary change in a case of High-grade B cell lymphoma with 11q aberration.

High-grade B cell lymphoma with 11q aberration (HGBCL-11q) is an aggressive lymphoma with a germinal center (GC) B cells phenotype. It is characterized by a cytogenetic alteration on the long arm of chromosome 11, which includes proximal gains and telomeric losses. HGBCL-11q shares certain morpho-phenotypic and gene expression features with Burkitt lymphoma (BL) but lacks the typical IG::MYC translocation. The current classifications consider HGBCL-11q as MYC rearrangement negative lymphoma. In contrast, in BL the characteristic 11q aberration is recognized as a secondary event occurring during clonal evolution. An increasing number of aggressive GC B cell lymphomas exhibiting both the typical 11q aberration and MYC rearrangement at the initial diagnosis are reported mostly as HGBCL, NOS (not otherwise specified). However, there is limited data on the temporal relationship between MYC rearrangement and the 11q aberration in these instances. Here, we present a case of nodal HGBCL-11q that shows a focal area with elevated MYC protein expression and a copy number gain of a rearranged MYC locus. These findings suggest that MYC rearrangement can occur as a secondary event in HGBCL-11q.