Enterochromaffin-like (ECL) cells are the dominant endocrine cell type in the oxyntic mucosa. Normally regarded as histamine-producing cells, they are exquisitely sensitive to the trophic action of gastrin and undergo a hyperplastic increase in a variety of hypergastrinemic conditions. A hyperplasia-neoplasia sequence of ECL-cell proliferations has been recently proposed, following the realization that increasingly severe degrees of ECL-cell hyperplasias over a period of several years can progress to ECL-cell carcinoids. Such carcinoids arising in patients with chronic hypergastrinemia differ both in their clinical and pathologic profiles from the sporadic carcinoids that occur in normogastrimenic individuals and, therefore, need to be distinguished from them. This distinction is particularly important for their clinical management, since antrectomy appears to be of benefit in ECL carcinoids of hypergastrinemic patients.