Pancreatic Neuroendocrine Neoplasias in Multiple Endocrine Neoplasia Type 1 Are Predominantly Located in the Dorsal Anlage: An Endoscopic Ultrasound Study

Objectives Pancreatic neuroendocrine neoplasias (pNENs) frequently occur in multiple endocrine neoplasia type 1 (MEN1). Their distribution referring to embryology, that is, the pancreatic anlagen, has not been investigated yet. Methods In the time between 1998 and 2019, we studied the distribution of pNENs in MEN1 concerning the embryologic origin of the pancreas, that is, the dorsal versus ventral anlage using endoscopic ultrasound in 117 MEN1 patients: 56 women, 61 men; aged 40 years (standard deviation, 14 years) at first endoscopic ultrasound. Results In 105 patients, a total of 628 pNENs were detected. They were located in the pancreatic tail: 231; pancreatic body: 177; pancreatic head/uncinate process: 220. Of the latter, 22 were located in the ventral anlage, 176 in the dorsal anlage, and 22 remained undefined. In summary, just 3.5% of all detected pNENs were located in the ventral anlage, 93.0% in the dorsal anlage, and 3.5% could not be assigned. Conclusions Our study indicates that the vast majority of pNENs in MEN1 is located in the dorsal anlage, whereas the ventral anlage of the pancreas seems to be to a large extend spared from pNENs. Implications for new surgical strategies might be considered.