Background: The role of advanced functional imaging techniques in prediction of pathological risk categories of gastrointestinal stromal tumors (GIST) is still unknown. The purpose of this study was to evaluate classical CT features, CT-perfusion and magnetic-resonance-diffusion-weighted-imaging (MR-DWI)-related parameters in predicting the metastatic risk of gastric GIST. Patients and methods: Sixty-two patients with histologically proven GIST who underwent CT perfusion and MR-DWI using multiple b-values were prospectively included. Morphological CT characteristics and CT-perfusion parameters of tumor were comparatively analyzed in the high-risk (HR) and low-risk (LR) GIST groups. Apparent diffusion coefficient (ADC) and intravoxel-incoherent-motion (IVIM)-related parameters were also analyzed in 45 and 34 patients, respectively. Results: Binary logistic regression analysis revealed that greater tumor diameter (p < 0.001), cystic structure (p < 0.001), irregular margins (p = 0.007), irregular shape (p < 0.001), disrupted mucosa (p < 0.001) and visible EFDV (p < 0.001), as well as less ADC value (p = 0.001) and shorter time-to-peak (p = 0.006), were significant predictors of HR GIST. Multivariate analysis extracted irregular shape (p = 0.006) and enlarged feeding or draining vessels (EFDV) (p = 0.017) as independent predictors of HR GIST (area under curve (AUC) of predicting model 0.869). Conclusion: Although certain classical CT imaging features remain most valuable, some functional imaging parameters may add the diagnostic value in preoperative prediction of HR gastric GIST.

Background: Gastrointestinal stromal tumors (GISTs) exhibit variable biological behavior, from indolent lesions to aggressive tumors with metastatic potential. Preoperative risk assessment is important for treatment planning. Therefore, this study evaluated the predictive value and reproducibility of CT morphological features in identifying high-risk GISTs using independent dual-reader analysis. Materials and Methods: This retrospective study included 26 patients with histopathologically confirmed gastric GISTs who underwent biphasic contrast-enhanced MDCT. Two radiologists independently evaluated CT morphological features, including tumor size, mucosal integrity, internal structure, shape, growth pattern, and enlarged feeding or draining vessels (EFDV). Based on disrupted mucosa and EFDV, tumors were stratified into high-risk (HR) and low-risk (LR) groups and correlated with histopathological findings. Results: Histopathological analysis confirmed HR GISTs in 10 and LR GISTs in 16 patients. Excellent interobserver agreement was observed for mucosal integrity (κ=0.843) and tumor structure (κ=0.923), with substantial agreement for EFDV and growth pattern, and moderate agreement for tumor shape and predicted risk. Both radiologists demonstrated high sensitivity (90%) for identifying HR GISTs. Larger tumor size, disrupted mucosa, heterogeneous structure, irregular shape, endophytic growth, and EFDV were associated with HR tumors, although specificity remained limited due to overlapping imaging features. Conclusion: CT-derived morphological features are valuable imaging biomarkers for preoperative risk stratification of gastric GISTs. Disrupted mucosa and enlarged peri-/intratumoral vessels were the strongest predictors of high-risk tumors. Despite overlapping imaging features between lowand high-risk lesions, conventional CT analysis may aid in identifying aggressive tumors and guiding treatment planning.

Background/Aim. KIT (KIT proto-oncogene receptor tyrosine kinase) and PDGFRA (platelet-derived growth factor receptor alpha) gene mutations represent major molecular forces inside the gastrointestinal stromal tumors (GIST). Aim of this study was to evaluate these mutations in the patients who underwent surgical resection of gastric GIST, but without imatinib mesylate treatment. Methods. Retrospective clinical study included patients who were operated on due to gastric GIST from November 2000 till November 2016. A molecular analysis of paraffin embedded tumor tissue was performed, and the patients with the presence of KIT and PDGFRA mutations were further evaluated, with regard to the pathological tumor stage, disease recurrence and overall survival. Results. Out of 45 patients in total, 43 patients had KIT and PDGFRA mutations, and 2 patients were classified as the wild type GIST. After curative resection, 11 patients were classified as a low risk GIST, 8 as an intermediate risk and 26 as a high risk GIST. The KIT mutations were present in 37 patients, most commonly as deletion in exon 11. The PDGFRA mutations were present in 6 patients. The presence of KIT mutation had a strong statistical correlation with the mitotic index (p = 0.021). After the ten-year follow-up, all patients with the PDGFRA mutations were alive, while those with the KIT mutations had a survival rate of 71% (p = 0.31). Conclusion. The presence of KIT exon 11 deletion in the patients with primarily resected gastric GIST is associated with the higher mitotic index and worse overall survival than those present with the PDGFRA mutations. This results suggest prognostic significance towards more aggressive behaviors.

As the most common mesenchymal tumors of the digestive tract, gastrointestinal stromal tumors (GIST) can have significant metastatic potential with a high rate of dissemination to the liver and peritoneal cavity. Based on the modified NIH (National Institutes of Health) classification, these tumors are classified into four stages: very low, low, intermediate and high-risk tumors. For low-risk tumors (LRG), minimally invasive surgery with R0 resection is the most common therapeutic option, while for high-risk tumors (HRG), imatinib adjuvant therapy is included post-surgically. Preoperative risk stratification is important for determining the therapeutic treatment and the patient's prognosis. With modern advances in diagnostic modalities, imaging analysis is no longer limited to visual assessment. As a modality of functional multidetector CT diagnostics, CT perfusion enables the quantification of tumor vascularization, while texture analysis provides a quantitative assessment of the degree of tumor heterogeneity, which overall can help in differentiating the metastatic potential of these tumors. The importance of morphological characteristics of tumors obtained by conventional CT examination in risk prediction has already been proven by numerous studies, and it is considered that, together with the advanced CT techniques mentioned above, it can provide a predictive model for the preoperative assessment of GIST risk stratification.

Aerodigestive fistulas represent a major challenge in clinical practice. This problem is burdened with severe morbidity and mortality, despite recent advantages in endoscopic endoluminal repair techniques. Special problems are fistulas localized higher, engaging the proximal esophagus and trachea, which in adults most often result from post-intubation injury. Surgery is generally demanding and reserved for the patients in whom other, less invasive options fail. Hereby, we present a case of post-intubation tracheoesophageal fistula, successfully treated with endoscopic vascular plug placement.

Radical esophagectomy remains the only potentially curative option in the treatment of esophageal cancer. However, this procedure is burdened with high morbidity and mortality rates, even in high-volume centers. A tracheo- or bronchoesophageal fistula (TBF) is rare but is one of the most difficult life-threatening complications following an esophagectomy for cancer treatment. Several classifications have been proposed regarding the localization of a TBF, its etiology, and the timing of its occurrence; hence, no classification is universally accepted. However, one of the most common etiological explanations for the formation of a TBF is a prior esophagogastric anastomotic leak. Treatment options include a conservative approach, which usually combines several endoscopic methods. Surgical treatment is directed towards fistula closure with direct suturing or, more often, the usage of pediculated flaps. Here, we present a patient with late TBF following a minimally invasive esophagectomy, which was surgically solved in an atypical way. We believe that this type of repair may be useful in patients in whom pedunculated flaps are not an option.