Mucosal duodenal cancer originating from a Peutz-Jeghers polyp: endocytoscopic features.

Peutz-Jeghers syndrome (PJS) is a rare disease, known to place affected individuals at high risk for the development of gastrointestinal cancer. Careful surveillance and early detection of gastrointestinal neoplasms in these patients is therefore mandatory. However, the mechanism by which gastrointestinal neoplasms develop in PJS patients remains controversial. Although a hamartoma-adenoma-carcinoma pathway has been proposed, some investigators oppose this theory.