Gastrointestinal stromal tumor: computed tomographic features.

OBJECTIVE: To describe anatomical distribution and CT findings of gastrointestinal stromal tumors in Srinagarind Hospital.

MATERIAL AND METHOD: The abdominal CT images of 16 patients (12 men, 4 women: mean age 49 +/- 17SD) with pathologically proven GISTs during 1998-2005 were retrospectively reviewed. The tumor sites, sizes, borders, growth patterns, patterns of enhancement, and sign of malignancy were evaluated. The findings of benign and malignant GISTs were compared.

RESULTS: Among sixteen patients, the most common location of GISTs was stomach (56.25%). The others were small bowel (43.75%), and tumor size larger than 5 cm. The present study found that the smooth and mixed smooth and irregular surface lesions are equal in number (50%). The growth was extraluminal in 56.25%. Almost all tumors had inhomogeneous density (n = 15). Intratumoral gas (43.75%), fluid (37.5%), and calcification (50.00%), were present in the tumors. All cases showed inhomogeneous contrast enhancement. The CT signs of malignancy found were invasion of the adjacent organ(s) (62.5%), lymphadenopathy (25%), liver metastasis/nodule (18.75%), ascites (6.25%), perilesional fat plane stranding (93.75%), and pleural effusion (6.25%).

CONCLUSION: The most common site of GISTs is the stomach. The typical tumors appear as inhomogeneous enhancing inhomogeneous extraluminal mass with either well-defined or irregular border. The CT findings cannot be used as a single tool for differentiating the benign from malignant GISTs.