Multiple myeloma with extramedullary plasmacytoma: pathogenesis and clinical case

Background . Multiple myeloma complicated by extramedullary plasmacytoma is an unfavorable variant of the disease. It remains unknown what triggers tumor transformation. The review presents literature data on pathogenesis disease, as well a clinical example comprehensive study substrate. Aim To molecular and biological characteristics substrate bone marrow using various research methods. Materials methods A 55-year-old patient was admitted to National Medical Research Center for Hematology with diagnosis multiple occurring retroperitoneal space. dNA isolated from samples different localization (blood plasma, Cd138+ cells, buccal epithelial cells). profile short tandem repeats (STR) obtained studied multiplex polymerase chain reaction followed fragment analysis. fluorescent in situ hybridization (fISH) cells performed probes. Comparative genomic microarray (arrayCGH) also performed. mutation KRAS, NRAS, BRAF genes Sanger sequencing localizations. Results induction therapy (vCd (bortezomib + cyclophosphamide dexamethasone), vRd lenalidomide daratumumab therapy) ineffective, death occurred 4 months after first manifestations appeared. Comparison STR markers circulating cell-free (cfdNA), revealed largest number involved loci exactly plasmacytoma’ dNA. NRAS gene found only This indicates presence another clone extra-medullary plasmacytoma. Molecular karyotyping arrayCGH method rearrangements many chromosomes. 1p32.3 bi-allelic deletion, amplification 1q21, 8q24/MyC del17p13 were confirmed fISH studies Conclusion genetic necessary understand mechanisms and, this basis, develop differentiated therapeutic approaches.