NK-Cell Lymphoblastic Leukemia/Lymphoma (Literature Review and Authors' Experience)

Abstract

Aim. To investigate clinical and laboratory features of NK-cell lymphoblastic leukemia/lymphoma (NK-LL). Methods. Of 161 patients treated in the Department of Chemotherapy of Hemoblastoses of the N.N. Blokhin Russian Cancer Research Center from 2000 to 2014, NK-LL was diagnosed in 1 patient (0.6 %). In the Laboratory of Hematopoietic Immunology of the N.N. Blokhin Russian Cancer Research Center, NK-LL was diagnosed in 3 more patients referred from other healthcare institutions over the same period of time. The disease was diagnosed in accordance with the 2008 WHO criteria. Therefore, the NK-LL group consisted of 4 patients (3 men and 1 woman) aged 29, 40, 59, and 82. Results. All patients had total bone marrow blast metaplasia (> 70 %) and extramedullary lesions in the form of generalized lymphadenopathy, hepatosplenomegaly, lesions of skin, tonsils, mediastinum, and CNS in the form of neuroleukemia. Cytochemical response in blast cells to myeloperoxidase, lipids, and nonspecific esterase was negative. In all patients, expression of CD56 antigen (69.8-99.1 %) and T-associated CD7 antigen (66.2-92.0 %) were found on blast cells. There was no expression of myeloid, T- and B-lymphoid antigens. In one patient, the PCR demonstrated no T-cell receptor gene chain rearrangement. The cytogenetic study was not performed in any patient. Induction therapy of NK-LL patients was carried out mainly according to treatment regimens for acute lymphoblastic leukemia. The complete remission (1 and 7 months) was achieved in 2 patients. The longest remission (20 months) was obtained using a combined regime RACOP for the treatment of a relapse. The life span after the diagnosis (beginning from the date on the initiation of therapy) was 1, 5, 17, and 29 months. Conclusion. The analysis demonstrates low efficacy of current regimens for treatment of NK-LL. The treatment success seems to depend on timely and accurate diagnosis of this complex, aggressive malignant tumor, as well as on development of new therapeutic approaches.