THE SPECTRUM OF GASTRIC NEUROENDOCRINE TUMORS - A CLINICOPATHOLOGICALAND IMMUNOCYTOCHEMICAL STUDY OF 27 CASES

Gastric neuroendocrine tumours are rare and clinicopathologically hete rogeneous. 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 carc inoids, six well differentiated neuroendocrine carcinomas, and three s mall cell carcinomas. Patients were followed up to November 1994 or to death. Archival paraffin sections were subjected to Grimelius', Masso n-Fontana, and Alcian blue-PAS procedures and immunocytochemically sta ined with antibodies to neuroendocrine markers, regulatory peptides, a lpha-HCG, serotonin, p53, bcl-2, and Ki67 antigen. Nonneoplastic gastr ic mucosa was evaluated for the presence of chronic atrophic gastritis , argyrophil cell status, and Helicobacter pylori. Our experience conf irmed heterogeneity of gastric neuroendocrine tumours having different clinicopathologic characteristics and outcome. Differences in gender, age, TNM categories, tumour size, site of origin, immunophenotype, an d outcome were observed for the three above mentioned histotypes. The size seemed to be a valid criterion of distinction both between carcin oids and neuroendocrine carcinomas and also within carcinoids. Breakdo wn of carcinoids into three different size classes revealed difference s related to the background against which the tumour arises and had al so prognostic implications. Within carcinoids, other prognostic featur es included status of nonantral mucosa and gastrinaemia.