Ampulla of Vater Neuroendocrine Tumor G1

**Semantic type:** Neoplastic Process

**Definition:** A well-differentiated, low-grade neuroendocrine neoplasm that arises from the ampulla of Vater and the periampullary region. The mitotic count is less than 2 per 2 mm2 and the Ki-67 index is less than 3%.

**Synonyms:** - Ampulla of Vater NET G1 - Neuroendocrine Tumor G1 of the Ampullary Region