May Be Caused by

 Common

Carcinoma of stomach extending to involve duodenum

Pancreatitis

Peptic ulcer disease

Prolapsed antral-pyloric fold

Prolapsed gastric mucosa

Prolapsed gastric polyp

Zollinger-Ellison syndrome

 Uncommon

Ascariasis

Crohn disease

Eosinophilic gastroenteritis

Ménétrier disease

Schistosomiasis

Strongyloidiasis

Tuberculosis