title: A rare case of multiple carcinoids and endocrine cell micronests in a patient with chronic duodenitis.
abstract: BACKGROUND
  To the authors' knowledge, multiple carcinoid tumors of the duodenum have not been reported previously. However, multiple carcinoids in the stomach, ileum, and rectum, which were accompanied by the proliferation of endocrine cells, have been reported in the published literature.
  
  
  METHODS
  A patient with multiple carcinoids including argyrophilic cell hyperplasia of the duodenum and hypergastrinemia underwent surgery. The resected stomach and duodenum were analyzed histopathologically.
  
  
  RESULTS
  There were 11 carcinoid lesions, each of which was accompanied by peripheral endocrine cell micronests (ECMs). Increasing gastrin positive cells in the antral region and chronic duodenitis in the duodenal bulb also were observed. The peripheral ECMs usually were adjacent to proliferating argyrophilic cells in the Brunner gland ducts or the crypts of Lieberkühn, which showed focal pyloric gland metaplasia.
  
  
  CONCLUSIONS
  In the case presented in the current study, the development of the multiple carcinoid lesions may be strongly related to the presence of multifocal pyloric gland metaplasia, as well as to the trophic action of gastrin, which is present at high levels in the setting of chronic duodenitis.
authors.affiliation: Hepatobiliarypancreatic Division, Department of Surgery, Graduate School of Medicine, University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Abe
authors.forename: K
authors.initials: K
authors.lastname: Kubota
authors.forename: T
authors.initials: T
authors.lastname: Oka
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Makuuchi
mesh_terms: D002276:Carcinoid Tumor / Q000209:etiology* / Q000473:pathology; D002908:Chronic Disease; D004382:Duodenitis / Q000150:complications* / Q000473:pathology; D019858:Enteroendocrine Cells / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008679:Metaplasia / Q000209:etiology; D008875:Middle Aged