title: Benign glandular downgrowth in gastric neuroendocrine neoplasms: a potential mimic of composite tumour.
abstract: OBJECTIVE
  We have observed glandular downgrowth in some gastric neuroendocrine tumours (NETs), in which nonneoplastic appearing gastric glands are admixed with submucosal neuroendocrine nests, that could potentially be confused with composite tumours.
  
  
  RESULTS
  We reviewed 68 gastric NETs with at least submucosal invasion, and evaluated associations between glandular downgrowth, clinical parameters (age, gender, NET setting) and tumour characteristics (size, depth of invasion, grade). Controls included 45 duodenal NETs. Glandular downgrowth was present in 28 (41%) gastric NETs but only 2 (4.4%) duodenal NETs (P < 0.0001). It was not related to age, gender, hypergastrinemia (downgrowth present in 43% of NETs arising in autoimmune gastritis, 41% of Zollinger-Ellison syndrome, 36% of sporadic NETs), tumour size, depth of invasion, or grade. Glandular downgrowth was confined to the submucosa even though 12 (18%) gastric NETs invaded muscularis propria. Submucosal gastric glands (pyloric type in 79%, intestinal in 50%, fundic in 29%) showed metaplastic changes similar to overlying mucosa, were usually mitotically inactive (64% of cases lacked mitotic figures), were geographically restricted to the NET, and never metastasized.
  
  
  CONCLUSIONS
  Our findings support the frequent occurrence and nonneoplastic nature of glandular downgrowth in gastric NETs, which should not be mistaken for composite tumours.
authors.affiliation: Department of Pathology, M. D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Maheshwari
authors.initials: M
authors.lastname: Ramineni
authors.forename: Melissa W
authors.initials: MW
authors.lastname: Taggart
authors.forename: Asif
authors.initials: A
authors.lastname: Rashid
authors.forename: Susan C
authors.initials: SC
authors.lastname: Abraham
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018193:Neoplasms, Complex and Mixed / Q000473:pathology*; D018358:Neuroendocrine Tumors / Q000473:pathology*; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000473:pathology*
keywords: composite; gastric; neuroendocrine; stomach