BIOPSY-FREE DIAGNOSIS OF PRIMARY DIFFUSE LARGE B-CELL LYMPHOMA OF THE CENTRAL NERVOUS SYSTEM

Introduction. The use of invasive methods for diagnosing primary diffuse large B-cell lymphoma of the central nervous system (PDLBCL CNS) and primary vitreoretinal lymphoma (PVRL) is often associated with the development of severe neurological deficits and disability of patients. A promising direction in the diagnosis of PDLBCL CNS and PVRL is the use of non-invasive approaches based on molecular genetic methods for the determination of mutations in the MYD88 gene in the cerebrospinal fluid (CSF), vitreous fluid (VF) and free circulating tumor DNA (cfDNA) in blood serum. Aim: to present the potential of non-invasive diagnosis of PDLBCL CNS and PVRL. Main findings. The study included 6 patients (4 - PDLBCL CNS, 2 - PVRL). The average age was 64 (54-75) years. Despite increased cytosis in the CSF in all 4 patients with PDLBCL CNS, the tumor population was determined by flow cytometry in only half of the cases. According to a molecular genetic study, mutations in the MYD88 gene with an allelic load from 2.5% to 15% were detected in the genomic DNA of the CSF of all patients. In 2 patients with PVRL, mutations in the MYD88 gene were detected in VF with an allelic load of 4.2% and 6.6%, which was the only confirmation of the diagnosis. Currently, 5 patients have completed the treatment program and 1 is undergoing therapy. All 5 patients are in complete remission (CR) of the disease with follow-up periods from 1 to 8 months.