title: An aggressive extranodal NK-cell lymphoma arising from indolent NK-cell lymphoproliferative disorder.
abstract: Indolent NK-cell lymphoproliferative disorder, also known as chronic natural killer (NK) cell large granular lymphocytosis (leukemia), is a very rare entity in the World Health Organization (WHO) Classification of Tumors of Hematopoietic & Lymphoid Tissues. Unlike aggressive NK-cell leukemia, which is malignant, the WHO does not specify whether indolent NK-cell lymphoproliferative disorder is reactive or neoplastic. Patients with indolent NK-cell lymphoproliferative disorder are usually asymptomatic older adults who have a nonprogressive, very stable clinical course. We report an unusual case of an aggressive extranodal NK-cell lymphoma, non-nasal type, which presented as a subcutaneous tissue mass, which apparently transformed from a preexisting, untreated indolent NK-cell lymphoproliferative disorder in an 65-year-old otherwise healthy white man. The extranodal NK-cell lymphoma and the NK-cell lymphoproliferative disorder in the blood and bone marrow share a distinctive and identical NK-cell immunophenotype and genotype: CD56/CD8/TIA-1-positive and surface CD3-negative, negative for Epstein-Barr virus infection, and no evidence of T-cell and B-cell receptor gene rearrangements. To the best of our knowledge, such aggressive lymphomatous transformation in an indolent NK-cell lymphoproliferative disorder has not been previously reported.
authors.affiliation: Division of Pathology, City of Hope National Medical Center, Duarte, CA, USA. qhuang@coh.org
authors.forename: Qin
authors.initials: Q
authors.lastname: Huang
authors.forename: Karen L
authors.initials: KL
authors.lastname: Chang
authors.forename: Karl K
authors.initials: KK
authors.lastname: Gaal
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Weiss
mesh_terms: D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D003520:Cyclophosphamide / Q000627:therapeutic use; D018450:Disease Progression; D004317:Doxorubicin / Q000627:therapeutic use; D017809:Fatal Outcome; D020275:Guillain-Barre Syndrome / Q000209:etiology; D006801:Humans; D007694:Killer Cells, Natural / Q000473:pathology*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy / Q000209:etiology / Q000473:pathology*; D008232:Lymphoproliferative Disorders / Q000150:complications*; D008297:Male; D011241:Prednisone / Q000627:therapeutic use; D012131:Respiratory Insufficiency / Q000209:etiology; D014750:Vincristine / Q000627:therapeutic use
chemical_list: D014750:Vincristine; D004317:Doxorubicin; D003520:Cyclophosphamide; D011241:Prednisone