Submucosal gastric lesions: a CECT-based tool for differential diagnosis between gastrointestinal stromal tumor and leiomyoma

Aim. To identify criteria for differential diagnosis between gastrointestinal stromal tumor (GIST) and gastric leiomyoma (GLe) in contrast-enhanced computed tomography (CECT).

Material and methods. We retrospectively analyzed CECT data of 65 patients with GIST and 19 patients with GLe. All cases were histologically and immunohistochemically proved. We evaluated tumor size, contours, growth type, extraorgan extension, invasion into the surrounding tissues, tumor calcification/ulceration/necrosis and regional lymph node status.

Results. Among 84 patients divided into two groups (65 patients with GIST and 19 with GLe, respectively) we found that tumor localization, heterogeneous enhancement, and intratumoral necrosis may be utilized for differential diagnosis. The prognostic value significantly increased with the use of relative density ratio (tumor density/ aorta density or tumor density/portal vein density in the arterial, venous, and delayed phases, respectively) compared to tumor density alone. It was found that malignant GISTs are characterized by a higher relative density ratio than leiomyomas in the venous phase.

Conclusion. We developed a prognostic model for differential diagnosis between GIST and GLe with a sensitivity of 90.8% and specificity of 89.5%. We created an online calculator that preoperatively determines probable tumor type (http://medstatistic.ru/giso.html).

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