Ampullary carcinoma of the duodenum: current clinical issues and genomic overview.

Ampullary carcinomas of the duodenum are uncommon. Moreover, the diversity in the clinical outcomes of these patients makes it difficult to interpret previous studies and clinical trial results. The difficulty in proper staging of ampullary carcinomas, especially with regard to the T category of the tumor in the TNM system, reflects the anatomic complexity and non-uniform histopathologic subtypes. One major reason for this difficulty in interpretation is that the tumors may arise from any of the three epithelia (duodenal, biliary, or pancreatic) that converge at this location. Generally, ampullary carcinomas are classified into intestinal and pancreaticobiliary types based on morphology and immunohistochemical features. While many studies have described their specific characteristics and clinical impact, the prognostic value of these subtypes is controversial. In recent years, whole-exome sequencing analyses have advanced our understanding of the genomic overview of ampullary carcinoma. Gene mutations serve as prognostic and predictive biomarkers for this disease. Therefore, basic knowledge of the genomic profile of ampullary carcinomas is required for surgeons to understand how best to apply precision medicine as well as surgery and adjuvant therapies. This review provides an overview of the current basic and clinical issues of ampullary carcinoma.