Multiple endocrine neoplasia type 1 with variant of unknown significance, in a patient after the diagnosed of pancreatic neuroendocrine neoplasia.

Duodenopancreatic neuroendocrine neoplasia (DP-NEN) is in approximately 10% of cases of multiple endocrine neoplasia type 1 (MEN1). We encountered a case in which the onset of NEN led to suspicion and diagnosis of MEN1. Although genetic testing showed variant of uncertain significance (VUS), we considered it pathological from the clinical course, promoting the provision of genetic counseling and screening for relatives. MEN1 has a variety of clinical manifestations, and DP-NENs are the second-most common manifestation after primary hyperparathyroidism (pHPT). It is important to assume that MEN1 is an underlying cause of NEN.