Passaro's triangle or gastrinoma triangle is a presumptive region in the abdomen between three points:

1. Superior—porta hepatis^[1] (earlier—confluence of the cystic and common bile duct),^[2]
2. Inferior—junction of the second and third portion of duodenum,^[2] and
3. Medial—junction of the neck and body of the pancreas^[2]

The importance of the triangle is because it is known as the source of origin of most gastrinomas.^[3][4] However, primary gastrinomas can also occur in the liver or extrahepatic bile ducts, commonly with metastasis to the local lymph nodes.^[5]

The appellation is due to Edward Peter Passaro, an American surgeon, who explained it for the first time.^[3]