A composite adenoendocrine carcinoma of the stomach arising from a neuroendocrine tumor

Gastric neuroendocrine tumors (carcinoids) are relatively uncommon neoplasms. Some 70 to 80% of these lesions occur in patients with autoimmune body gastritis. This disorder, however, is also a risk factor for the development of conventional gastric adenocarcinomas. We report a case of a patient with autoimmune body gastritis and a well-differentiated neuroendocrine tumor of the stomach, which was removed with endoscopic full-thickness resection in sano upon signs of invasive growth several years after its first diagnosis. Histological examination surprisingly showed a composite glandular-endocrine gastric carcinoma. We discuss the histopathological genesis of the tumor and provide evidence that endoscopic full-thickness resection might be an oncologically appropriate minimally invasive treatment for such gastric lesions.