[Clinicopathological and molecular genetic features of Burkitt-like lymphoma with 11q aberration]

Objective: To investigate the clinicopathological features, molecular genetics, treatment and prognosis of Burkitt-like lymphoma with 11q aberration (BLL-11q). Methods: Six cases of BLL-11q diagnosed at the First Affiliated Hospital of Zhengzhou University, from January 2016 to January 2020 were reviewed and analyzed using hematoxylin-eosin staining, immunohistochemistry, EBER in situ hybridization and fluorescence in situ hybridization. Clinical information including follow-up data was collected and analyzed. Results: The median age of the six immunocompetent patients was 29 years (range 20-38 years) and the male to female ratio was 5∶1. All patients had nodal disease in the head and neck region. Five patients had Ann Arbor stage Ⅰ-Ⅱ disease, while one patient had stage Ⅳ disease. Lymph nodes showed partial or total architectural effacement by a diffuse proliferation of monomorphic lymphocytes. Four cases were morphologically similar to Burkitt lymphoma, and two cases were unclassified with histological features between Burkitt lymphoma and diffuse large B-cell lymphoma. Mitotic figures, apoptosis and necrosis were conspicuous. Five cases exhibited the"starry sky"pattern. CD20, CD10 and bcl-6 were diffusely and strongly positive. The Ki-67 index was more than 95%. The follicular-dendritic-cell meshwork was noted in one case using CD21 stain. C-MYC was expressed variably. CD3, bcl-2, MUM-1, CD30 and TDT were negative in all cases. EBER in situ hybridization was also all negative. FISH analyses using C-MYC, bcl-2 and bcl-6 break-apart probes were all negative. All cases had the 11q23.3 gain/11q24.3 loss pattern, and 11q23.3 amplification was found in one case. IgH and IRF4 break-apart probes analysis was also negative. All patients were alive with no disease after a follow-up of 4 to 19 months. Conclusion: BLL-11q is a rare lymphoma that resembles Burkitt lymphoma morphologically and phenotypically, but lacks C-MYC gene rearrangements. Instead, it has a chromosome-11q alteration characterized by proximal gains and telomeric losses. It's necessary to improve our understanding of BLL-11q to avoid misdiagnosis and missed diagnosis.