The spectrum of gastric neuroendocrine tumours: A clinicopathologic and immunocytochemical study of 27 cases

Gastric neuroendocrine tumours are rare and clinicopathologically heterogeneous. Clinical management of patients is still controversial and requires further investigations. The aim of the present report was to review the clinicopathologic and immunocytochemical characteristics of the gastric neuroendocrine tumours observed at our Institution in the period 1975-1994. Twenty-seven cases were studied, including: 18 carcinoids, six well differentiated neuroendocrine carcinomas, and three small cell carcinomas. Patients were followed up to November 1994 or to death. Archival paraffin sections were subjected to Grimelius', Masson-Fontana, and Alcian blue-PAS procedures and immunocytochemically stained with antibodies to neuroendocrine markers, regulatory peptides, alpha-HCG, serotonin, p53, bcl-2, and Ki67 antigen. Nonneoplastic gastric mucosa was evaluated for the presence of chronic atrophic gastritis, argyrophil cell status, and Helicobacter pylori. Our experience confirmed heterogeneity of gastric neuroendocrine tumours having different clinicopathologic characteristics and outcome. Differences in gender, age, TNM categories, tumour size, site of origin, immunophenotype, and outcome were observed for the three above mentioned histotypes. The size seemed to be a valid criterion of distinction both between carcinoids and neuroendocrine carcinomas and also within carcinoids. Breakdown of carcinoids into three different size classes revealed differences related to the background against which the tumour arises and had also prognostic implications. Within carcinoids, other prognostic features included status of nonantral mucosa and gastrinaemia.