Gastric Ulcer with Gastrocolic fistula due to a Zollinger- Ellison Syndrome (27 of 33)

Over 90% of gastrinomas are found within an anatomic
triangle referred to as the gastrinoma triangle. The 3 points
that define this region are: (1) the confluence of the cystic
and common bile duct, (2) the junction of the second and
third portions of the duodenum, and (3) the junction of the
neck and body of the pancreas. Recent evidence suggests
that gastrinomas occur at least as frequently in the
duodenal wall as in the head of the pancreas within this
triangle. Gastrinomas vary in size, ranging from 0.1 cm to
more than 20 cm in diameter. In at least 50% of cases,
these tumors are multiple. Less commonly, gastrinomas
may be found in the hilum of the spleen, in the stomach,
liver, or parapancreatic and mesenteric lymph nodes. A
small number of ovarian tumors have been shown to be
gastrinomas. Although up to two thirds of gastrinomas are
malignant, it is difficult to determine on histologic
appearance alone. Even when malignant, these tumors are
slow growing. However, a small number of patients with
gastrinomas have tumors that grow and metastasize rapidly.
Patients with gastrinomas limited to lymph nodes tend to
survive for long periods, often over 20 years, without tumor
progression. The presence of liver metastases reduces life
expectancy to about 8 years.