title: Composite gastric carcinoma. Report of a tumor of the carcinoma-carcinoid spectrum.
abstract: A composite tumor of the gastric antrum composed of areas of adenocarcinoma and poorly differentiated carcinoid is described, with histochemical and immunohistochemical documentation of endocrine and nonendocrine differentiation. The neoplasm maintained a composite architecture both within the site of origin and in lymph node metastases. The adenocarcinoma displayed a predominantly tubular architecture with focal sheets of clear cells. The poorly differentiated carcinoid was argyrophilic, chromogranin immunoreactive, and focally serotonin immunoreactive, and contained keratin intermediate filaments in a distinctive distribution suggestive of endocrine differentiation. Among the tumors of the carcinoma-carcinoid spectrum, the composite tumor is less common than either carcinomas with interspersed endocrine cells or carcinoids with interspersed nonendocrine cells.
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology / Q000473:pathology* / Q000556:secondary / Q000648:ultrastructure; D002276:Carcinoid Tumor / Q000276:immunology / Q000473:pathology* / Q000556:secondary / Q000648:ultrastructure; D002864:Chromogranins / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D007382:Intermediate Filaments / Q000648:ultrastructure; D007633:Keratins / Q000276:immunology; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000276:immunology / Q000473:pathology* / Q000556:secondary / Q000648:ultrastructure
chemical_list: D002864:Chromogranins; D007633:Keratins