Emerging Concepts in Gastric Neoplasia: Heritable Gastric Cancers and Polyposis Disorders.

Hereditary gastric cancer is a relatively rare disease with specific clinical and histopathologic characteristics. Hereditary gastric cancer of the diffuse type is predominantly caused by germline mutations in CDH1. The inherited cause of familial intestinal gastric cancer is unknown. Gastric adenocarcinoma and proximal polyposis of the stomach is a hereditary cancer syndrome caused by germline mutations in promoter 1B of APC. Other well-defined cancer syndromes, such as Lynch, Li-Fraumeni, and hereditary breast or ovarian cancer syndromes, are associated with increased risk of gastric cancer. This article reviews important histopathologic features and emerging concepts regarding gastric carcinogenesis in these syndromes.