Three subtypes of gastric argyrophil carcinoid and the gastric neuroendocrine carcinoma: a clinicopathologic study.

BACKGROUND: Enterochromaffinlike (ECL) cell carcinoids recently observed in rats stimulated new interest in gastric endocrine tumors arising in humans.

METHODS: Paraffin-embedded sections of 55 endocrine tumor cases were stained with H&E, mucin tests were performed, and immunoperoxidase was used for detecting endocrine markers; 23 cases were also investigated ultrastructurally.

RESULTS: Forty-five argyrophil carcinoids, 9 neuroendocrine carcinomas, and 1 gastrinoma were identified. Three clinicopathologic subtypes of carcinoids were characterized: (1) twenty-eight cases, none metastatic, arose in a background of body-fundus atrophic gastritis and hypergastrinemia; (2) seven cases, 2 locally metastatic, were associated with hypertrophic gastropathy and hypergastrinemia due to multiple endocrine neoplasia/Zollinger-Ellison syndrome; and (3) ten were sporadic cases, 7 of which were deeply invasive, 6 metastatic, and 5 histologically atypical. All carcinoids showed histochemical and ultrastructural patterns of ECL cells. The 9 neuroendocrine carcinomas, all deeply invasive and metastatic, were composed of anaplastic, small- to intermediate-sized cells with high mitotic index and focal necrosis.

CONCLUSIONS: Gastrin-promoted carcinoids represent a benign or low grade tumor disease, whereas sporadic carcinoids and neuroendocrine carcinomas are life-threatening neoplasms, independent of gastrin promotion.