Gastrointestinal Adenomatous Polyposis Associated with Small Cell Neuroendocrine Carcinoma of the Rectosigmoid: A case report

ABSTRACT

In adenomatous polyposis coli there are many colonic and extracolonic manifestations, and various combinations of these induce different clinical presentations and syndromes. We experienced a unique case of adenomatous polyposis of the large intestine and stomach in a 39-year-old man. In the colon, small cell neuroendocrine carcinoma rather than adenocarcinoma had developed, which did not contain adenomatous or carcinomatous foci. The adenomatous polyps in the colon were all small and sessile with no cancerous or precancerous change two years after the resection of the symptomatic gastric adenomas, even though the gastric adenomas were larger and showed dysplastic change. We think this case is another variant of adenomatous polyposis syndrome.