Gastric GIST: A Rare Cause of Upper GI Bleeding

Gastrointestinal stromal tumours are the most common mesenchymal tumours of the gastrointestinal tract. This case report highlights the necessity of early surgical intervention in such cases to avoid mortality due to bleeding and to raise the awareness of rare causes of upper gastrointestinal bleed and their management. A 19 year old male presented in the surgery department of Shaheed Suhrawardy medical College Hospital with complaints of recurrent episodes of melena with anorexia and weight loss for 6 months. Apart from anaemia no significant findings were noted on physical examination. Investigations including upper GI endoscopy was not conclusive. So he underwent laparotomy which revealed an exophytic growth along the lesser curvature. Lower partial gastrectomy was done and histopathological and immunohistochemistry report showed evidence of benign low risk GIST. As the tumor was benign with no malignant potential imatinib therapy was not advocated. J Shaheed Suhrawardy Med Coll 2020; 12(2): 119-122

Development and validation of a novel diagnostic model for initially clinical diagnosed gastrointestinal stromal tumors using an extreme gradient-boosting machine

Introduction Gastrointestinal stromal tumor (GIST) is the most common gastrointestinal soft tissue tumor. Clinical diagnosis mainly relies on enhanced CT, endoscopy and endoscopic ultrasound (EUS), but the misdiagnosis rate is still high without fine needle aspiration biopsy. We aim to develop a novel diagnostic model by analyzing the preoperative data of the patients. Methods We used the data of patients who were initially diagnosed as gastric GIST and underwent partial gastrectomy. The patients were randomly divided into training dataset and test dataset at a ratio of 3 to 1. After pre-experimental screening, max depth = 2, eta = 0.1, gamma = 0.5, and nrounds = 200 were defined as the best parameters, and in this way we developed the initial extreme gradient-boosting (XGBoost) model. Based on the importance of the features in the initial model, we improved the model by excluding the hematological features. In this way we obtained the final XGBoost model and underwent validation using the test dataset. Results In the initial XGBoost model, we found that the hematological indicators (including inflammation and nutritional indicators) examined before the surgery had little effect on the outcome, so we subsequently excluded the hematological indicators. Similarly, we also screened the features from enhanced CT and ultrasound gastroscopy, and finally determined the 6 most important predictors for GIST diagnosis, including the ratio of long and short diameter under CT, the CT value of the tumor, the enhancement of the tumor in arterial period and venous period, existence of liquid area and calcific area inside the tumor under EUS. Round or round-like tumors with a CT value of around 30 (25–37) and delayed enhancement, as well as liquid but not calcific area inside the tumor best indicate the diagnosis of GIST. Conclusions We developed a model to further differential diagnose GIST from other tumors in initially clinical diagnosed gastric GIST patients by analyzing the results of clinical examinations that most patients should have completed before surgical resection.

Endocarditis following an unsuccessful attempt to remove a gastric GI stromal tumor by laparoscopic endoscopic cooperative surgery

Gastrointestinal Stromal Tumors (GIST) are the most common subepithelial lesions of the gastrointestinal tract. Treatment of lesions greater than 2 cm in diameter is by laparoscopic wedge resection. We report a 77-year-old man who was diagnosed with a 2.3 cm diameter gastric GIST. He had a thickened mitral valve, severe mitral annular calcification, mild mitral regurgitation and moderate aortic stenosis. One week after undergoing an unsuccessful attempt at Laparoscopic Endoscopic Cooperative Surgery (LECS), he was admitted with a fever of 40.2o C. Blood cultures grew Staphylococcus lugdunensis. Transthoracic and transesophageal echocardiography revealed moderate mitral regurgitation and an 8 X 5 mm vegetation on the mitral valve and posterior annulus. This is the first report of endocarditis following LECS. Physicians need to be aware of this possible complication. Keywords: endocarditis; GI stromal tumor; endocarditis; endoscopic tumor.

Laparoscopic Transgastric Resection of a Large Gastric GIST: A Case Report and Review of Literature

Introduction Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal (GI) tract. Their primary treatment is surgical. Case Report Here we report a case of a 36-year-old male patient who was being evaluated for weakness, anemia, and melena. Upper GI endoscopy showed a mass projecting into the lumen and an abdominal computed tomography (CT) confirmed a well-defined mass close to the lesser curvature on the posterior wall. An endoscopic ultrasound-guided fine needle aspiration suggested a diagnosis of GIST. After optimization, the patient was taken up for a laparoscopic transgastric resection of the GIST. The resected specimen measured 9.5 × 8.5 × 7.5 cm. Postoperatively, the patient recovered well and was discharged by the fifth postoperative day. Discussion While traditionally, open surgery has been advocated for GISTs, for fear of spillage and peritoneal seeding, the role of minimal access surgery has been growing in recent years. The use of a transgastric approach avoids the potential complication of luminal stenosis following a wedge resection of a tumor close to the cardia. Because lymphadenectomies are rarely required and local invasion is uncommon, a wide local resection is usually curative. Thus, a laparoscopic approach can be considered as the first line in uncomplicated GISTs, irrespective of tumor size.

Development and Validation of a Novel Diagnostic Model for Initially Clinical Diagnosed Gastrointestinal Stromal Tumors Using An Extreme Gradient-Boosting Machine

INTRODUCTION Gastrointestinal stromal tumor (GIST) is the most common gastrointestinal soft tissue tumor. Clinical diagnosis mainly relies on enhanced CT, endoscopy and endoscopic ultrasound (EUS), but the misdiagnosis rate is still high without fine needle aspiration biopsy. We aim to develop a novel diagnostic model by analyzing the preoperative data of the patients. METHODS We used the data of patients who were initially diagnosed as gastric GIST and underwent partial gastrectomy. The patients were randomly divided into training dataset and test dataset at a ratio of 3 to 1. After pre-experimental screening, max depth = 2, eta = 0.1, gamma = 0.5, and nrounds = 200 were defined as the best parameters, and in this way we developed the initial extreme gradient-boosting (XGBoost) model. Based on the importance of the features in the initial model, we improved the model by excluding the hematological features. In this way we obtained the final XGBoost model and underwent validation using the test dataset. RESULTS In the initial XGBoost model, we found that the hematological indicators (including inflammation and nutritional indicators) examined before the surgery had little effect on the outcome, so we subsequently excluded the hematological indicators. Similarly, we also screened the features from enhanced CT and ultrasound gastroscopy, and finally determined the 6 most important predictors for GIST diagnosis, including the ratio of long and short diameter under CT, the CT value of the tumor, the enhancement of the tumor in arterial period and venous period, existence of liquid area and calcific area inside the tumor under EUS. Round or round-like tumors with a CT value of around 30 (25–37) and delayed enhancement, as well as liquid but not calcific area inside the tumor best indicate the diagnosis of GIST. CONCLUSIONS We developed a model to further differential diagnose GIST from other tumors in initially clinical diagnosed gastric GIST patients by analyzing the results of clinical examinations that most patients should have completed before surgical resection.

Endoscopic Resection of Gastrointestinal Stromal Tumor: Is It Safe?

Recently, results from clinical studies of endoscopic resection of gastrointestinal stromal tumor (GIST) in the stomach are being reported. This procedure has several advantages, such as the provision of a definite diagnosis and therapeutic plan, avoidance of frequent follow-up examination, and reduction of patients’ anxiety. However, several concerns also exist such as a limited number of studies, low R0 resection rate, and relatively shorter follow-up period compared with surgical resection. Nevertheless, it is encouraging that most of the post-procedural complications have been treated with conservative management and that some of the patients did not show recurrence of the tumor during long-term follow-up. The selection of suitable cases and the experience of the endoscopists are the most important factors for successful endoscopic resection of gastric GIST. Development of novel procedures as well as collaboration with laparoscopic surgeons are currently in progress.

616 Rare KIT gene mutation in a recurrent GIST: Case Report

Introduction The diagnosis and treatment of Gastro-intestinal stromal tumours (GISTs) has been revolutionized by molecular pathology and targeted therapy. Description This patient was diagnosed with locally advanced gastric GIST in 2009. He was initially treated neoadjuvantly with imatinib from 2009- 2010. He underwent laparoscopic resection in 2010. Pathology showed almost complete response with only 1.5mm focus of viable tumour. He did not receive adjuvant imatinib as this was not established practice in 2010. Recurrent disease was resected in 2011. Mitotic count was 200/50hpf. Adjuvant imatinib was given for 5 years then discontinued in 2016. Imaging showed no recurrence over this time period. Molecular testing showed Kit Exon 11 mutation- this is common in GISTs and associated with response to imatinib. Recurrent disease was diagnosed 2018 with a 10x9cm mass between residual stomach and liver– he recommenced imatinib with partial response (maximal response was reached in 2020, but a new 3cm lesion was noted) He underwent further resection of the residual stomach and liver segmentectomy in 2020. Histology showed acellular areas of myxoid degeneration, indicating treatment response however viable tumour remained. Sequencing was performed. This showed the expected mutation in exon 11 but also a mutation in exon 13 of KIT- this has been shown recently to confer resistance to imatinib. Discussion Over 90% of GISTs harbour mutations in c-KIT. Recent work has demonstrated that some tumours acquire secondary mutations conferring resistance, following prolonged TKI therapy. Radiological and histopathological features correlate with such events and assist in deciding surgical management.