**5. Clinical picture**

About 60% of GISTs occur in the stomach, 30% in the jejunum and ileum, 5% in the duodenum, 2–3% in the rectum, 1–2% in the colon, and < 1% in the esophagus [4]. About 70% of GISTs are symptomatic, 20% are asymptomatic, and 10% are discovered at autopsy [41]. The main symptoms of GIST are GI bleeding, abdominal discomfort, and abdominal mass. GISTs are highly vascular tumors and may grow quickly and cause massive gastrointestinal or intraperitoneal hemorrhage [42]. Obstruction symptoms such as dysphagia, obstructive jaundice, and small bowel obstruction may also occur [42].

Extragastrointestinal GISTs occur in less than 10% of GISTs and mainly occur intra-abdominally and affect omentum and mesentery. Such tumors are considered more aggressive than gastric GIST and have a poorer prognosis similar to small bowel GISTs [43, 44].

About 50% of patients will present with metastatic disease with the most common site of metastasis being liver at about 65%. Other common metastatic sites are omentum and peritoneum. Extra-abdominal metastasis, lung bone, and lymph node metastasis are not common [13].
