On normal upper gastrointestinal tract examinations the papilla and associated structures may be identified along the medial wall of the second portion of the duodenum (see figure). The papilla is an elevated mound of tissue that is typically smaller than 1 cm. It is considered abnormal when larger than 1.5 cm, although healthy patients have been known to have papillae enlarged up to 3 cm. Inferior to the papilla, folds may be visible, extending up to 3 cm in length.

The papilla is usually enlarged as a result of benign disease. The most common cause of edema of the papilla is the presence of stones in the distal common bile duct. Other causes include pancreatitis (either short term or long term), which can produce swelling (Poppel’s sign). Typically the enlargement of the papilla with edema produces a smooth and symmetrical enlargement. Rarely, acute duodenal ulcer disease produces papillary enlargement but is usually associated with duodenal fold thickening. A choledochocele, an abnormal enlargement of the most distal end of the common bile duct and ampullary region, also causes enlargement of the papilla.

Tumors arising in or about the papilla are called perivaterian malignancies. Carcinoma of the papilla is the most common tumor. Polyps or mesenchymal tumors, such as leiomyoma, can also arise in the region and produce enlargement. Certain polyposis syndromes—familial polyposis coli and the associated Gardner’s syndrome—predispose patients to tumor development in the perivaterian region. Such a patient can require routine screening of the upper gastrointestinal tract throughout his or her life because of this association.