Source:http://linkedlifedata.com/resource/umls/id/C1332244
NCI: An adenoma that arises from the ampulla of Vater and resembles the adenomas of the small and large intestines. Morphologically, according to the growth pattern, it may be classified as tubular, tubulovillous, or villous. Dysplasia is always present. Jaundice may be an early symptom.