To compare CT features of gastrointestinal stromal tumors (GIST) with those of lymphomas in the small intestine.

CT findings of 11 pathologically confirmed GIST patients and 10 lymphoma patients were retrospectively reviewed. CT findings were analyzed with regard to location, size, margin, growth patterns, internal character, enhancement, invasion, vascular encasement, lymphadenopathy, intestinal obstruction and ascites.

An extraluminal mass was present in 82% (9/11) of the GIST patients versus 30% (3/10) of the lymphoma patients. Circumferential wall thickening was observed in 80% (8/10) of the lymphoma patients (p<.05). Internal necrosis or gas was present in 73% (8/11) of the GIST patients versus 10% (1/10) of the lymphoma patients (p<.05). Inhomogeneous enhancement was observed in 63% (7/11) of the GIST patients compared to homogeneous enhancement in 90% (9/10) of the lymphoma patients (p<.05). Lymphadenopathy was only observed in 80% (8/10) of the lymphoma patients (p<.05). In other findings such as fatty infiltration, ascites and intestinal obstruction there were no statistically significant differences (p>.05).

Features revealed by CT scans are highly useful in differentiating GIST from lymphoma of the small intestine. Extraluminal growth and internal necrosis or gas are more common in patients with GIST compared with lymphoma. CT features of circumferential wall thickening and associated lymphadenopathy are more common in patients with lymphoma.