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

G G Karmazanovsky,E A Sokolova,D I Marapov,E A Martirosyan,A V Glotov

doi:10.24835/1607-0763-2020-4-27-41

G G Karmazanovsky, E A Sokolova + Show 3 more

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https://doi.org/10.24835/1607-0763-2020-4-27-41

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Abstract

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).

Highlights

While the majority of gastric tumors are epithelial or lymphomas, about 3% of all tumors are non-epithelial tumors [1]
Contours, growth type, extraorgan extension, invasion into the surrounding tissues, tumor calcification/ulceration/necrosis and regional lymph node status
Among 84 patients divided into two groups (65 patients with gastrointestinal stromal tumor (GIST) and 19 with gastric leiomyoma (GLe), respectively) we found that tumor localization, heterogeneous enhancement, and intratumoral necrosis may be utilized for differential diagnosis

Summary

Introduction

While the majority of gastric tumors are epithelial or lymphomas, about 3% of all tumors are non-epithelial tumors [1]. Before immunohistochemistry (IHC) became a common practice in modern research methodology, tumors that are today classified as GISTs were considered to be smooth muscle tumors: leiomyomas, leiomyosarcomas, and leiomyoblastomas [2]. The discovery of a mutation in c-cit protooncogene, which is characteristic for GISTs, allowed to classify them in a group separate from smooth muscle tumors [3]. In terms of their histological structure, leiomyomas are similar to normal smooth muscle cells; they are the most common mesenchymal tumors of the esophagus and rarely found in the stomach. GISTs are believed to be the most common mesenchymal tumors of the stomach [4]. The standard approach for stomach GISTs up to 2 cm in size is an endoscopic ultrasound evaluation followed by surveillance

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