Myelodysplastic/myeloproliferative neoplasm with t(2;11)(P21;Q23)del(5) (Q22;Q33) but without mixed-lineage leukemia (MLL) rearrangement; [Mijelodisplazna/mijeloproliferativna neoplazma sa t(2;11)(P21;Q23)del(5) (Q22;Q33) ali bez mixed-lineage leukemia (MLL) rearanžmana]

Abstract

Introduction. Myelodysplastic/myeloproliferative neoplasms represent a group of rare hematologic malignancies with con-comitant characteristics of two different disorders. There are cytopenias and cytoses with dysplastic morphology in the circu-lating blood and hyperplastic bone marrow, respectively. Many cytogenetic and molecular features have been found in this rare entity, but t(2;11)(p21;q23)del(5) (q22;q33) has not been de-scribed so far. Case report. We present a patient with myelo-dysplastic syndrome, subtype refractory anemia without ringed sideroblasts, with unique translocation t(2;11)(p21;q23) associ-ated with del(5)(q22;q33) in the karyotype. Fluorescence in situ hybridization analysis did not detect mixed-lineage leukemia (MLL) rearrangement, which can be found in other hematolog-ic malignancies with this translocation. After a year on support-ive treatment with packed red cells, thrombocytosis developed with a concurrent increase in white blood cells and the Janus kinase-2 gene mutation. This confirmed the presence of myel-odysplastic/myeloproliferative neoplasms. Due to the high platelet count, the cerebrovascular insult has occurred. The pa-tient was treated supportively and with lenalidomide. After in-troducing the lenalidomide steadily, the patient's condition im-proved, the peripheral blood count normalized, and he became transfusion independent. Conclusion. Patients with the cyto-genetic finding of t(2;11)(p21;q23) associated with del(5)(q22;q33) but without MLL rearrangement and with Ja-nus kinase-2 gene mutation presence, respond to lenalidomide therapy and have relatively longer overall survival. © 2021 Inst. Sci. inf., Univ. Defence in Belgrade. All rights reserved.