title: Foveolar gastric metaplasia presenting as a duodenal tumor with an atypical appearance: a case report.
abstract: BACKGROUND
  Foveolar gastric metaplasia of the duodenum is a frequent but not as yet considered correlate of endoscopically detected duodenal polyps. The majority of foveolar gastric metaplasias associated with polyps presented a typical benign endoscopic appearance and they were diagnosed by biopsy. Here we report a case of a surgical-resected foveolar gastric metaplasia manifesting as a duodenal tumor with an atypical appearance.
  
  
  METHODS
  An asymptomatic 56-year-old Asian man who presented with a foveolar gastric metaplasia of atypical appearance and had previously undergone esophagogastroduodenoscopy was referred to our hospital. A biopsy revealed a normal duodenum with an inflamed mucosa. Narrow band imaging with magnifying endoscopy revealed normal microvessels with normal micromucosa, which indicated non-neoplasia. Endoscopic ultrasonography using a miniature probe system (20 MHz) revealed a hypoechoic mass with multiple anechoic lesions (16-mm diameter) located in the mucosal layer. The lesion was excised via laparotomy assisted by endoscopic techniques similar to endoscopic submucosal dissection. The pathology indicated foveolar gastric metaplasia.
  
  
  CONCLUSIONS
  Foveolar gastric metaplasia can present as a duodenal tumor. We identified two important clinical issues. First, foveolar gastric metaplasia can present as a duodenal tumor with an atypical benign appearance. Second, both endoscopic ultrasonography and narrow band imaging are useful techniques to increase the diagnostic rate of this condition.
authors.affiliation: Department of Endoscopy, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Abe
authors.affiliation: Department of Endoscopy, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan. masakato89@gmail.com.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kato
authors.affiliation: Department of Surgery, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan.
authors.forename: Shuzo
authors.initials: S
authors.lastname: Kohno
authors.affiliation: Department of Pathology, Clinical Service, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan.
authors.forename: Sigeharu
authors.initials: S
authors.lastname: Hamatani
authors.affiliation: Department of Endoscopy, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kawahara
authors.affiliation: Department of Endoscopy, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Isshi
authors.affiliation: Department of Endoscopy, The Jikei University Katsushika Medical Center, 6-41-2 Aoto Katsushika-ku, Tokyo, 125-8506, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: Department of Endoscopy, The Jikei University School of Medicine, 3-25-8 Nishishinbashi Minato-ku, Tokyo, 105-8461, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sumiyama
mesh_terms: D003937:Diagnosis, Differential; D004378:Duodenal Diseases / Q000473:pathology* / Q000601:surgery; D004386:Duodenum / Q000473:pathology*; D016145:Endoscopy, Digestive System; D005753:Gastric Mucosa / Q000473:pathology*; D006801:Humans; D007417:Intestinal Polyps / Q000473:pathology* / Q000601:surgery; D007813:Laparotomy; D008297:Male; D008679:Metaplasia / Q000473:pathology*; D008875:Middle Aged; D016896:Treatment Outcome
keywords: Ectopic gastric mucosa; Endoscopic ultrasonography (EUS); Foveolar gastric metaplasia (FGM); Narrow band imaging (NBI)