３６ Mucosal change of the stomach with low-grade mucosa- associated lymphoid tissue lymphoma after eradication of Helicobacter pylori : Follow-up study of 48 cases Shahnaz Begum＊, Toshiaki Sano＊, Hideko Endo＊, Hitoshi Kawamata†, and Yoshihito Urakami‡ ＊Department of Pathology, The University of Tokushima School of Medicine, Tokushima, Japan ; †Department of Oral and Maxillofacial Surgery, The University of Tokushima School of Dentistry, Tokushima, Japan ; and ‡Urakami Gastro Clinic, Tokushima, Japan Abstract : Low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach has been demonstrated to be closely linked to Helicobacter pylori (H. pylori) and to be frequently remissioned after the cure of H. pylori infection. Several previous studies have focused on proliferating lymphocytes but little is known about gastric epithelial change and the duration of the remission after the cure of H. pylori infection. We performed a long-term follow-up investigation on the effects of anti-H. pylori treatment on MALT lymphoma and chronic gastritis at the histologic and molecular levels. Forty-eight patients with low-grade gastric MALT lymphoma and 28 chronic gastritis patients in whom H. pylori infection was eradicated were studied. After eradication, 43 MALT lymphoma patients showed complete histologic remission and continuous remission was observed during follow-up for up to 43 months (mean, 17.8 months). As for epithelial changes after eradication, “emptiness of lamina propria” was more pronounced in the mucosa with MALT lymphoma than that with chronic gastritis, and its severity in MALT lymphoma cases significantly decreased during the observation period whereas the glandular area increased. Cystic change of the fundic gland also occurred more frequently in MALT lymphoma cases than chronic gastritis cases. B-cell clonality before eradication analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) was detected in almost all MALT lymphoma cases (43 cases), but rare in chronic gastritis cases (6 cases). After eradication, in spite of histologic regression, 21 MALT lymphoma patients had a persistent monoclonal population during the follow-up period. B-cell monoclonality preceding the malignant transformation was noted in 4 cases. These observations indicate that 1) complete histologic remission of low-grade gastric MALT lymphomas seems stable even if a monoclonal B cell population is detectable in some cases, 2) there may be a stage of disease where monoclonal B cells are present but there is no histologic evidence of MALT lymphoma, and 3) regenerative change of the damaged glands may occur in histologic regressed MALT lymphoma cases. J. Med. Invest. 47 : 36-46, 2000 Key words : low-grade MALT lymphoma, epithelial change, empty lamina propria, B-cell clonality, H. pylori, eradication, long-term follow-up INTRODUCTION Received for publication November 29, 1999 ; accepted January 5, 2000. Malignant lymphomas of the mucosa-associated Address correspondence and reprint requests to Prof. Toshiaki lymphoid tissue (MALT) type are an extra-nodal Sano, Department of Pathology, The University of Tokushima School of Medicine, Kuramoto-cho, Tokushima 770-8503, Japan marginal-zone B-cell lymphoma (1, 2) and the most and Fax : +81-88-633-9423. common of all gastric lymphomas (3). They may be The Journal of Medical Investigation Vol. 47 2000 The Journal of Medical Investigation Vol. 47 2000 ３７ either low or high-grade (2). In low-grade MALT upper gastrointestinal symptoms. All previous clini- lymphomas of the stomach, small- to medium-sized cal records and histopathologic slides were checked irregular neoplastic B lymphoid cells, so-called if previous history presented. In MALT lymphoma centrocyte-like cells, densely infiltrate the lamina cases, the involvement of lymph nodes or other propria and surround, occasionally invading, the organs was assessed by physical examination, reactive-type follicles with germinal centers (1, 4). routine laboratory tests, chest x-ray, thoracic and They also characteristically invade and destroy the abdominal CT and abdominal ultrasound analysis, epithelium of the gastric glands to form lympho- and the lesion was confined to the stomach. epithelial lesions (1, 4). High-grade MALT lymphomas, in which neoplastic B lymphoid cells are larger and Tissue specimens apparently atypical, may either arise de novo or be On each occasion, the endoscopy was undertaken transformed from low-grade MALT tumors (2). by the same endoscopist (Y.U.). The endoscopic It is currently accepted that Helicobacter pylori findings alone could not discriminate between (H. pylori) plays a causative role not only in chronic chronic gastritis and low-grade MALT lymphoma active gastritis, peptic ulcer diseases and probably before eradication. Six to ten biopsy specimens gastric carcinomas (5-7) but also in gastric low-grade were taken from suspicious areas for histology and MALT lymphomas (8-10). Clinical studies have two others for reverse transcriptase-polymerase reported high remission rates for low-grade MALT chain reaction (RT-PCR) study. The biopsy specimens lymphomas after the cure of H. pylori infection (8-10). were immediately fixed with 10% neutral buffered However, little is known about the duration of the formalin and kept at room temperature for one day. remission because long-term follow-up study is Thin sections were routinely prepared and stained limited (11). Moreover, data are also limited with for hematoxylin and eosin and Giemsa. Biopsy regard to the epithelial changes in the stomach materials for RT-PCR were stored without fixation with MALT lymphomas during a long follow-up at -80℃ until use. period. The development of the polymerase chain reaction (PCR) provides a sensitive tool for the identification Eradication and follow-up of neoplastic B cell populations by the analysis of All 76 patients received anti-H. pylori therapy immunoglobulin heavy chain (IgH) gene. However, consisting of a combination of lansoprazole (30 mg/ the significance of the detection of B-cell monoclonality day), metronidazole (500 mg/day) and amoxicillin in gastric lymphoproliferative lesions by PCR re- (1.5 g/day) for 7 to 14 days. All patients underwent mains controversial, because monoclonality can be endoscopy two to four months after completion of detected not only in neoplastic (8-10) but also in the eradication therapy, and histologic and molecular histologically reactive lesions (10, 12, 13). Its clinico- analysis was done. Subsequently MALT lymphoma pathological significance has yet to be established. patients underwent repeated endoscopic, histologic The aims of this histologic and molecular study and molecular analysis at approximately six-month on H. pylori-associated gastric lymphoproliferative intervals for up to 45 months after anti-H. pylori diseases including low-grade MALT lymphomas therapy (mean, 20.2 months) (Fig.1), although 2 and chronic gastritis are 1) to assess the duration of of them (Cases 26 and 27 in Fig.1) were referred the remission, 2) to clarify the relationship between for surgical treatment. Patients whose initial biopsies histologic change and B-cell clonality, and 3) to were assessed as showing a reactive lymphoid investigate the epithelial changes over a long-term infiltrate (chronic gastritis) were followed up only follow-up period after eradication of H. pylori. once or twice for up to 33 months (mean, 8.4 months) after eradication treatment. MATERIALS AND METHODS Histologic criteria Patients Histopathologic grading for differential diagnosis Seventy-six patients with H. pylori-infected gastric of gastric lymphoid proliferative lesions was done lymphoproliferative lesions, either chronic gastritis using the scoring system of Wotherspoon et al .(8). or low-grade MALT lymphoma, were studied. All Briefly, grades up to 3 were considered reactive patients had initially presented with nonspecific (chronic gastritis) and grades 4 and 5 neoplastic ３８ S. Begum et al. Follow-up histologic study of 48 MALT lymphomas Case Case No Age/Sex No Age/Sex Group 1 : Histologically and molecularly regressed cases Group 3 : Persistent monoclonal cases after histologic regression -H. pylori eradication therapy was given ; ●-MALT lymphoma, histologically ; ○-Histological regression occurred ; ◎-Chronic gastritis, histologically ; ■-Monoclonal by PCR ; □-Polyclonal by PCR ; □-PCR was not performed ; ▲-Surgical treatment was given. For example, ● means histologically MALT lymphoma and monoclonal by PCR Fig.1. Histopathologic and RT-PCR results during follow-up for 48 low-grade gastric MALT lymphoma patients. (low-grade MALT lymphoma). The criteria for the Table 1. Sequences of primers for PCR diagnosis of low-grade gastric MALT lymphomas (For immunoglobulin heavy chain) were the detection of lymphoepithelial destruction, (Upper-stream) and the presence of dense diffuse infiltrates of VH1LS ; 5’-CAT GGA CTG GAC CTG GAG G-3’ centrocyte-like cells in lamina propria and germinal VH2+4LS ; 5’-CAT GAA ACA CCT GTG GTT CTT-3’ centers. Presence or absence of lymphoepithelial VH3LS ; 5’-GGG CTG AGC CTG GGT TTT CCT T-3’ lesions, lymphoid aggregates and lymphoid follicles VH5LS ; 5’-GGG GTC AAC CGC CAT CCT-3’ was evaluated for differential diagnosis. VH6LS ; 5’-TCT GTC TCC TTC CTC ATC TTC-3’ (Down-stream) µ Measurement of the degree of “empty lamina propria” C ;5’-GGT TGG GGC GGA TGC ACT-3’ (For nested) Histologic change in the degree of so-called“empty VHFR2 ; 5’-GC(C/T) (C/T)CC GG(A/G) AA(A/G) lamina propria”was morphometrically