80 Gastrointestinal Stromal Tumor

Clinical Presentation

A 77-year-old man presents with abdominal pain.

Fig. 80.1 Contrast-enhanced CT scan shows a lobulated, heterogeneously enhancing mass arising from the proximal stomach (arrow).

Radiologic Findings

An abdominal computed tomography (CT) scan (Fig. 80.1) shows a large, lobulated, heterogeneously enhancing mass arising from the proximal stomach.

Differential Diagnosis

Gastric adenocarcinoma
Leiomyoma/leiomyosarcoma
Schwannoma/neurofi broma
Metastasis

GISTs are the most common mesenchymal tumors arising from the gastrointestinal (GI) tract wall. Nevertheless, they are uncommon, accounting for only 1 to 3% of all GI neoplasms, and usually affect patients > 50 years of age without any gender predilection. These tumors are also reported to occur in 10 to 25% of patients affected by neurofibromatosis 1. Previously mistaken for smooth muscle and neural tumors, GISTs show distinctive genetic and histologic features. They can occur anywhere from the rectum to the esophagus, the stomach being the most common site of origin; they can also be located in the mesentery, omentum, and retroperitoneum.