The Value of Computed Tomography in Differentiating Heterotopic Pancreas from Small Gastrointestinal Stromal Tumor.

BACKGROUND: It is critical for an accurate preoperative diagnosis of heterotopic pancreas (HP) and small gastrointestinal stromal tumor (GIST), given the unique treatment and prognosis of the two tumors. This study aims to investigate HP's computed tomography (CT) features and identify the distinguishing characteristics between HP and small GIST.

METHODS: From January 2016 to August 2020, our hospital database was searched for confirmed histopathological results and CT scans for HP and GIST for further analysis. The statistically significant variables were determined by using Fisher's exact test, the Mann-Whitney U test, the receiver operating characteristic (ROC) curve and the inverse probability weighting method.

RESULTS: CT images and clinical data were reviewed for 24 participants with HP and 34 patients with small GIST. Contour, border, relative enhancement grade, surface dimple, duct-like structure, short diameter (SD), attenuation of each lesion in the unenhanced phase (Lp), and the enhancement ratio of tumor in the venous phase (ER) were significant for differentiating HP from small GIST. Threshold values for SD and Lp were 1.40 cm and 42.33 Hounsfield units, respectively. Ill-defined border, surface dimple, ductlike structure, and Lp were independent factors that differentiated HP from small GIST. Additionally, SD and ER were also found to be independent factors.

CONCLUSIONS: Contour, relative enhancement grade, SD, and Lp could effectively differentiate HP from small GIST, demonstrating improved diagnostic performance compared to other parameters. The presence of ductlike structures and surface dimples could further characterize HP. These findings may help distinguish HP from small GIST and avoid unnecessary invasive examination and therapy in individuals with asymptomatic HP.