Multiple duodenal epithelial tumors in a patient with polymerase proofreading-associated polyposis in POLE variant.

Polymerase proofreading-associated polyposis (PPAP) is a rare disease with autosomal-dominant inheritance caused by germline variants in the POLE and POLD1 genes. PPAP has been reported to increase the risk of multiple cancers, including colon, duodenal, and endometrial cancers. Herein, we report a case in which multiple duodenal tumors led to the detection of a POLE mutation. A 43-year-old woman underwent esophagogastroduodenoscopy (EGD). Multiple duodenal tumors were detected, and all lesions were treated endoscopically. The patient had a history of multiple colorectal cancers and endometrial cancer along with a family history of cancer; hence, genetic testing was performed, and POLE variant, c.1270C > G (p.Leu424Val) was detected. Hereditary colorectal cancer syndromes should be considered in patients with colorectal cancer who have multiple cancers or a family history of cancer, and multigene panel sequencing is useful in confirming the diagnosis. In addition, duodenal tumors frequently coexist in patients with PPAP-carrying POLE variants, while the endoscopic treatment for duodenal tumors becomes safe and useful with several new approaches. Therefore, surveillance EGD is necessary in such patients for the early detection and treatment of duodenal tumors.