title: Lymphomatoid gastropathy: a distinct clinicopathologic entity of self-limited pseudomalignant NK-cell proliferation.
abstract: Diagnostic errors in distinguishing between malignant and reactive processes can cause serious clinical consequences. We report 10 cases of unrecognized self-limited natural killer-cell proliferation in the stomach, designated as lymphomatoid gastropathy (LyGa). This study included 5 men and 5 women (age, 46-75 years) without any gastric symptoms. Gastroscopy showed elevated lesion(s) (diameter, ∼ 1 cm). Histologically, medium-sized to large atypical cells diffusely infiltrated the lamina propria and, occasionally, the glandular epithelium. The cells were CD2(+/-), sCD3(-), cCD3(+), CD4(-), CD5(-), CD7(+), CD8(-), CD16(-), CD20(-), CD45(+), CD56(+), CD117(-), CD158a(-), CD161(-), T cell-restricted intracellular antigen-1(+), granzyme B(+), perforin(+), Epstein-Barr early RNA(-), T-cell receptor αβ(-), and T-cell receptor γδ(-). Analysis of the 16 specimens biopsied from 10 patients led to a diagnosis of lymphoma or suspected lymphoma in 11 specimens, gastritis for 1 specimen, adenocarcinoma for 1 specimen, and LyGa or suspected LyGa for 3 specimens. Most lesions underwent self-regression. Three cases relapsed, but none of the patients died. According to conventional histopathologic criteria, LyGa is probably diagnosed as lymphoma, especially as extranodal natural killer/T-cell lymphoma, nasal type. However, LyGa is recognized as a pseudomalignant process because of its clinical characteristics. The concept of LyGa should be well recognized.
authors.affiliation: The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan. kentakeuchi-tky@umin.net
authors.forename: Kengo
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yokoyama
authors.forename: Shin
authors.initials: S
authors.lastname: Ishizawa
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Terui
authors.forename: Kimie
authors.initials: K
authors.lastname: Nomura
authors.forename: Kousuke
authors.initials: K
authors.lastname: Marutsuka
authors.forename: Maki
authors.initials: M
authors.lastname: Nunomura
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Fukushima
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yagyuu
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Nakamine
authors.forename: Futoshi
authors.initials: F
authors.lastname: Akiyama
authors.forename: Kazuei
authors.initials: K
authors.lastname: Hoshi
authors.forename: Kosei
authors.initials: K
authors.lastname: Matsue
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Hatake
authors.forename: Kazuo
authors.initials: K
authors.lastname: Oshimi
mesh_terms: D000368:Aged; D015153:Blotting, Western; D020031:Epstein-Barr Virus Infections / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D015321:Gene Rearrangement; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D007124:Immunoenzyme Techniques; D016130:Immunophenotyping; D017403:In Situ Hybridization; D007694:Killer Cells, Natural / Q000378:metabolism / Q000473:pathology*; D016399:Lymphoma, T-Cell / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013272:Stomach Diseases / Q000378:metabolism / Q000473:pathology* / Q000821:virology
chemical_list: D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta