title: Stage IV intramucosal gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type.
abstract: A 45-year-old woman with no symptoms underwent upper gastrointestinal endoscopy. A discolored area was noted at the greater curvature of the gastric upper body. Endoscopic ultrasonography demonstrated thickening of the second sonographic layer indicating that the depth of invasion was confined to the mucosa. A urea breath test and anti-Helicobacter pylori antibody test were negative. A computed tomography scan showed a consolidation at the right lung. Gastric biopsy and transbronchial lung biopsy (TBLB) demonstrated a monotonous proliferation of atypical small lymphocytes. A diagnosis of gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type (MALT lymphoma) was made. The clinical stage was stage IV. A genetic analysis showed rearrangement of the joining region of the immunoglobulin heavy chain gene and identical clones in both lesions. An API2-MALT1 fusion gene was detected in the gastric lesion. After H. pylori eradication treatment, combination treatment with rituximab plus CHOP (R-CHOP) was performed; 6 months later an endoscopy revealed complete disappearance of the lesion. Multiple gastric biopsies showed no infiltrating atypical lymphocytes. Similarly, the lesion in the lung showed complete remission (CR) on CT and TBLB. This report shows that a gastric MALT lymphoma located in the mucosa and disseminated to the lung maintained CR by R-CHOP.
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan. mohtaka@yamanashi.ac.jp.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ohtaka
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sato
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Shouji
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Ryouta
authors.initials: R
authors.lastname: Sueki
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Uetake
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohtsuka
authors.affiliation: Department of Hematology, University of Yamanashi, Chuo, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Iwao
authors.affiliation: Department of Hematology, University of Yamanashi, Chuo, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Kirito
authors.affiliation: First Department of Internal Medicine, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Enomoto
keywords: API2–MALT1 fusion gene; Intramucosal gastric marginal zone B cell lymphoma of mucosa-associated lymphoid tissue type; Lung involvement; R-CHOP; Stage IV