title: Complete remission of gastric plasmacytoma following eradication of "Candidatus Helicobacter heilmannii".
abstract: This is the first case report of gastric plasmacytoma associated with "Candidatus Helicobacter heilmannii" ('H. heilmannii') infection. The patient was a 40-year-old woman with epigastric discomfort. Upper gastrointestinal endoscopy demonstrated a white granular lesion on the wall of the gastric body. Histological studies showed numerous eosinophilic globules expanding the lamina propria mucosae. Immunohistochemically, the cells with these globules stained positive for CD138, CD79a, immunoglobulin (Ig) M, and kappa light chain, but negative for CD20, IgG, IgA, and lambda light chain. A diagnosis of plasmacytoma was made. Although a Helicobacter pylori infection was not detected, the patient received H. pylori eradication treatment. Two months after H. pylori eradication treatment, an upper gastrointestinal endoscopy showed a reduction of the white granular lesion. Eighteen months after eradication treatment, endoscopy, endoscopic ultrasonography and histological studies revealed complete remission of the lesion. No relapse has been documented 30 months after the initial diagnosis of plasmacytoma. Retrospectively, analysis of biopsy specimens removed before eradication treatment demonstrated that this patient had 'H. heilmannii' infection. Therefore, H. pylori eradication therapy should be considered as a potential first-line therapy for early-stage gastric plasmacytoma with or without H. pylori infection.
authors.affiliation: First Department of Internal 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, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Tatsumi
authors.affiliation: First Department of Internal Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Fukasawa
authors.affiliation: First Department of Internal 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, 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, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohtsuka
authors.affiliation: First Department of Internal 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, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Enomoto
authors.affiliation: Pathology and Cytology Laboratories, BML Inc., Tokyo, Japan.
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Pathology, School of Medicine, Juntendo University, Tokyo, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Mitani
keywords: Candidatus Helicobacter heilmannii; Complete remission; Gastric plasmacytoma; Helicobacter pylori eradication therapy; Spiral-shaped helicobacter