NK-cell neoplasms in Japan

Abstract

Neoplasms putatively originating from precursor and mature natural killer (NK) cells are rare, and their clinical features are unclear. A nationwide survey was performed in Japan to clarify the clinical features of these neoplasms diagnosed between 1994 and 1998, and data for 237 patients who met the criteria for putative NK cell-lineage neoplasms were analyzed. Among them, 11 had myeloid/NK-cell precursor acute leukemia, 15 blastic NK-cell lymphoma, 21 precursor NK-cell acute lymphoblastic leukemia, 22 aggressive NK-cell leukemia/lymphoma, 149 nasal-type NK-cell lymphoma (123 nasal and 26 extranasal) and 19 chronic NK lymphocytosis. The median overall survival time of patients with aggressive NK-cell leukemia/lymphoma was 2 months, which for chronic NK lymphocytosis was more than 8 years, and that for the other types of NK-cell neoplasms was between 6 and 22 months. Nasal NK-cell lymphoma and extranasal NK-cell lymphoma share the same histology. The age of affliction was the same, but the sex was different with males predominantly having nasal NK-cell lymphoma and females extranasal NK-cell lymphoma. Patients with extranasal NK-cell lymphoma had the tendency to exhibit a more advanced state of disease, with significantly higher International Prognostic Index and LDH levels, and significantly lower hemoglobin and platelet levels. The overall survival, however, did not differ significantly. Precursor NK-cell acute lymphoblastic leukemia and blastic NK-cell lymphoma were arbitrarily defined by the presence or absence of 30% or more of blastic cells in the bone marrow or peripheral blood, but there were no significant differences for affected age, gender, involved sites or prognosis. Aggressive NK-cell leukemia/lymphoma and extranasal NK-cell lymphoma were arbitrarily defined by the presence or absence of 30% or more of large granular lymphocytes in the bone marrow or peripheral blood and it is possible that aggressive NK-cell leukemia/lymphoma is a leukemic phase of extranasal NK-cell lymphoma. The incidence of skin involvement, however, was significantly higher for extranasal NK-cell lymphoma, suggesting that the two diseases are different. In nasal NK-cell lymphoma, Epstein-Barr virus in tumor cells was detected in all patients tested, suggesting its causative role.

Regression of the tumor after withdrawal of cyclosporine in relapsed extranodal natural killer/T cell lymphoma following allogeneic hematopoietic stem cell transplantation

“…Advanced-stage or relapsed ENKL is known for its poor prognosis [3,4], and its optimal therapeutic strategy remains to be determined. Although autologous HSCT may have some benefits even to advanced-stage ENKL, if patients are in CR at transplantation, the results of this approach have been disappointing in patients not in CR [6][7][8].…”

“…For some patients with localized-stage ENKL, conventional treatments including radiotherapy and/or chemotherapy can be curative [5]. However, the prognosis of patients with advanced-stage or relapsed ENKL remains poor [3,4]. In this population, long-term survival has been reported in very limited patients.…”

“…Although ENKL is quite rare in North America and Europe, it is more prevalent in East Asia and Central and South America [2]. Approximately 70-80% of ENKL patients are diagnosed as having a localized-stage disease, and the sites of predilection are the nasal cavity and the nasopharynx [2][3][4]. For some patients with localized-stage ENKL, conventional treatments including radiotherapy and/or chemotherapy can be curative [5].…”

Pediatric Natural Killer Cell Malignancy

“…The ratio of patients with UAT-ENKL as compared to those with NUAT-ENKL is 7:2 in adults and 2:1 in pediatric patients (Table 4). In pediatric patients, the frequency of NUAT-ENKL patients is higher than in adults [Oshimi et al, 2005]. In pediatric ENKL patients, about half of them presented UAT-ENKL: nine patients had a nasal site and three patients had an extranasal site, including mastoid, tonsil, and skin.…”

Aggressive Mature Natural Killer Cell Neoplasms: from Disease Biology to Disease Manifestations

“…Aggressive NK-cell leukemia is very rare and has a fulminant clinical course [2,[28][29][30][31][32]. Patients often present with systemic symptoms, BM involvement, pancytopenia, hepatosplenomegaly and abnormal liver function, and frequently develop HS, multiorgan failure and disseminated intravascular coagulation [33][34][35][36][37][38][39].…”