[The duodenum and Vater's papilla: tumors and tumor-like lesions--a clinico-pathologic discussion].

Tumors and tumor-like lesions of the duodenum and the Vater's ampulla are discussed in a clinical-pathological conference. Tumors and precancerous conditions are rarely found in the duodenum and the ampulla, nevertheless these areas should be investigated carefully during endoscopy of the upper gastrointestinal tract. About 12-15% of lesions described as tumors or tumor-like lesions are located in the duodenum. Histological findings of biopsy material from this region are the main topic of the conference. Incidence and differential diagnosis of the typical endoscopical and histological findings of the different tumors and tumor-like lesions are described.