Stage IV Gastrointestinal Stromal Tumor of Colonic Interposition in Esophagus

Abstract

Purpose: Gastrointestinal stromal tumors (GISTs) is the most common mesenchymal tumor of the gastrointestinal tract. GISTs predominant in the stomach (60-70%) and intestine (20-25%), but rarely occur in the esophagus (5%) and colorectum. A 47-year-old man with a history of recurrent intermittent chest pain for >6 months who was found to have a widened mediastinum on chest film. He has a history of lye ingestion in 1981 with gastric pull up and colonic interposition. He reported a 40 lbs weight loss with decreased appetite for 8 months. Review of systems was otherwise negative. Patient had fever of 101°F. Blood pressure, pulses and respiratory rate were normal. Physical exam is non-contributory. Laboratory evaluation was normal except for urine toxicology which was positive for cocaine. Chest film showed prominence of the left hilum and multiple retrosternal lucencies are likely represent bowel containing anterior diaphragmatic hernia. CT scan of chest showed a giant mediastinal mass with vessels running through it in continuity with the stomach, heart, aorta and pulmonary artery. Multiple rounded enhancing hypodensities were found in the liver in CT. Upper endoscopy revealed a large, ulcerated and cratered mass measuring 7cm in diameter and involving 75% of luminal circumference of the colonic interposition was seen 29-36cm from the incisors. EUS of the liver lesions showed well circumscribed hypoechoic masses easily accessible for FNA. FNA biopsy revealed malignant cells positive for CD34, CD117 and DOG1, consistent with GIST. Most GISTs occur in the sub diaphragmatic gastrointestinal tract; only a few cases have been reported in the esophagus. Our patient has GIST in a segment of colon that was used as an esophageal graft. Patient has been treated with Gleevec (a targeted therapy that is directed to the exact molecular abnormality that drives the GIST tumor) and followed up with CT and PET scans, which are sensitive for evaluating the extent of tumor progression. This is the first case of a giant metastatic GIST that involved a colonic interposition.Figure: [577] CT scan of chest.