A 25-year-old woman with a gastric GIST and a PET-positive epicardial tumor.

Background: A 25-year-old woman presented with a history of abdominal pain. Endoscopy of the upper gastrointestinal tract revealed a tumor that protruded into the prepyloric antrum. After resection, a 'high-risk' gastrointestinal stromal tumor was histologically confirmed.

Investigations: Endoscopy, endoscopic ultrasound, hemigastrectomy, [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT scan, histological examination, immunohistochemistry, cardiac MRI, high-resolution CT with electrocardiogram gating, CT angiography, and cardiac surgery.

Diagnosis: Gastrointestinal stromal tumor, epicardial paraganglioma, and Carney's syndrome.

Management: Abdominal ultrasound and endoscopy combined with endoscopic ultrasound, annual FDG-PET/CT scan.