title: Distinct morphologic, phenotypic, and clinical-course characteristics of indolent peripheral T-cell lymphoma.
abstract: Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) consists of a heterogeneous group of lymphomas. Patients generally show an aggressive clinical course and very poor outcome. Although the 2008 World Health Organization classification of PTCL-NOS includes 3 variants, low-grade lymphoma is not included. Of 277 PTCL-NOS cases recorded in our consultation files, we examined the clinicopathologic characteristics of 10 patients with T-cell lymphomas composed of small-sized cells with slight nuclear atypia. Eight patients showed extranodal involvement (5 patients, spleen; 3 patients, thyroid), and 5 patients were at clinical stage I or II. Histologically, all samples presented diffuse infiltrate of small lymphoid cells, with few mitotic figures. Immunohistologically, all samples were positive for CD3, and CD20 was detected in 5 samples. All samples showed a low Ki-67 labeling index (mean, 1.05%), and 7 samples were positive for central memory T-cell markers. Clonal T-cell receptor γ chain and/or α-β chain gene rearrangements were detected in all 10 patients. Five patients received chemotherapy, whereas for 3 patients, treatment consisted only of observation following surgical resection of the spleen or thyroid. Nine patients were alive at a median follow-up time of 19.5 months, whereas 1 patient died of an unrelated disease. The present study strongly indicates that T-cell lymphoma with small-sized lymphoma cells and a low Ki-67 labeling index is a distinct variant. Recognition of this novel lymphoma subtype, which should not be defined merely as PTCL-NOS, should be seriously considered.
authors.affiliation: Department of Pathology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama 700-8558, Japan.
authors.forename: Eiko
authors.initials: E
authors.lastname: Hayashi
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Takata
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Sato
authors.forename: Yukie
authors.initials: Y
authors.lastname: Tashiro
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Tachiyama
authors.forename: Seiko
authors.initials: S
authors.lastname: Sawada-Kitamura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Hiramatsu
authors.forename: Shun
authors.initials: S
authors.lastname: Sugiguchi
authors.forename: Soichiro
authors.initials: S
authors.lastname: Nose
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Hirokawa
authors.forename: Midori
authors.initials: M
authors.lastname: Ando
authors.forename: Lamia
authors.initials: L
authors.lastname: Abd Alkader
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Maeda
authors.forename: Mitsune
authors.initials: M
authors.lastname: Tanimoto
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yoshino
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000473:pathology; D049109:Cell Proliferation; D017024:Chemotherapy, Adjuvant; D002999:Clone Cells; D005260:Female; D015332:Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor / Q000235:genetics; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor / Q000235:genetics; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor / Q000235:genetics; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D016411:Lymphoma, T-Cell, Peripheral / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D013160:Splenic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen
keywords: CD20; Good prognosis; Indolent PTCL; Ki-67; Memory T cell