Intravascular large B-cell lymphoma with isolated bone marrow involvement

Introduction. Intravascular large B-cell lymphoma is a rare variant of large B-cell, highly invasive extranodal tumors of the lymphatic system. The pathogenesis of the disease lies in the ability of tumor cells to penetrate into small vessels and capillaries of various organs. The clinical presentation is atypical for diffuse large B-cell lymphoma. In the relevant literature, information on the diagnosis and treatment of this pathology is extremely rare, therefore each publication makes a significant contribution to expanding the horizons of hematologists and morphologists.Aim – to present a case of diagnosing intravascular B-cell lymphoma.Main findings. A clinical case of a 78-year-old patient who fell ill acutely is presented. At the onset of the disease, febrile fever was noted. In the general blood test: hemoglobin – 104 g/L; erythrocytes – 3.0 × 1012/L; ESR – 24 mm/h; platelets – 112 × 109/L, leukocytes – 4.9 × 109/L, 4 % of cells with lymphoblast morphology were found in the leukocyte formula. Blood serum tests revealed: an increase in uric acid concentrations – up to 639 μmol/L, LDH – up to 1885 U/L, beta-2-microglobulin – up to 8.9 mmol/L, C-reactive protein – up to 0.6 g/L, a decrease in the concentration of total protein – up to 45 g/L, an increase in the concentration of aspartate aminotransferase – up to 48 units/L at normal concentrations of bilirubin and alanine aminotransferase.The histological and immunohistochemical picture, according to the study of bone biopsy, most corresponded to bone marrow damage by intravascular large B-cell lymphoma. Immunophenotyping was carried out – 15.7 % of blast cells with immunophenotype CD19+HLA/DR+CD24+CD37+CD20+CD10+IgM+ were detected. Cytogenetic studies revealed no karyotype abnormalities. The result of fluorescence in situ hybridization of the IGH locus (14q32) was normal. Based on the data obtained, the final clinical diagnosis was established: diffuse large B-cell lymphoma, stage IVB, intravascular variant with bone marrow involvement, aggressive course. The patient was prescribed the first line of therapy according to the R-CHOP scheme (rituximab, cyclophosphamide, vincristine, prednisolone). In the control study of the bone marrow, after the first course of therapy, the number of lymphoid elements was 3.6 %, laboratory parameters returned to normal.