BACKGROUND & OBJECTIVE: Mesenchymal tumor of the GASTROINTESTINAL tract comprises a diverse group of neoplasms which occurs in adults. With recognition of immunohistochemical profile in recent years, GASTROINTESTINAL STROMAL tumor (GIST) has been grouped separately from other sarcomas. No therapeutic modality except. Surgey has ever demonstrated definitive evidence of clinical benefit in GIST. These TUMORS occur most commonly in the stomach, followed by small intestine, and are rare in the colon and rectum and extremely rare in the esophagus. GIST also arises rarely in the omentum, mesentery and peritoneum.CASE: A 69-year-old male was admitted to surgical ward with clinical and CT scan findings of large, movable abdominal mass behind the stomach with probable origin from the pancreas. Explorative laparatomy revealed an 18 x 16 cm mass in lesser omentum. Pathological and immunohistochemical techniques revealed malignant GIST.CONCLUSION: GASTROINTESTINAL STROMAL tumor should be considered in the differential diagnosis of the abdominal mass.

Introduction & Objective: GASTROINTESTINAL STROMAL TUMORS are the most common mesenchymal TUMORS of gastro intestinal tract. These TUMORS have lower prevalence compared to tumor arising from mucosa. So there is less evidence about them. This article tries to summarize present studies in this area.Materials & Methods: Among 2257 articles found in medline, 158 articles were selected because of their more relevance. After more evaluation, 58 papers were used for our summary.Results: The incidence of GASTROINTESTINAL STROMAL TUMORS is mostly in the fifth and sixth decades if life. These TUMORS originate from mesenteric ganglion cells. Most of these TUMORS express C-kit and CD34 antigens, which enable differentiation of these TUMORS from other mesenchymal TUMORS. Clinical manifestation of these TUMORS is not specific and the most common manifestation is long-lasting GASTROINTESTINAL bleeding.Endoscopic and endosonographic evaluations are helpful in diagnosis of these lesions.Conclusions: Complete surgical resection of these TUMORS is the basis of treatment. Imatinib which inhibits intracellular tyrosine kinase, is an effective medical treatment, and is used in patients with unresectable or metastatic TUMORS, both as neoadjuvant and as adjuvant treatment.

Introduction: Numerous studies have investigated the prevalence, incidence and clinical manifestations of GASTROINTESTINAL STROMAL TUMORS (GISTs). However, little is known about GISTs in Iran. This pioneer study focuses on description of 36 patients with GISTs in Iran.Methods: A database was created for 36 patients suffering from GIST who were treated in Loghman Medical Center and Tehran Cancer Institute in Tehran, Iran. Information on age, sex, clinical manifestations, treatment and outcomes were recorded and analyzed using SPSS version 13.Results: Patients had an average age of 60 years; and 16 of them were males. The disease was most commonly manifested by abdominal mass, weight loss, and anemia. Twenty one patients had a mass smaller than 10cm; and in 33 patients KIT test was positive. In the follow-up, 5 patients experienced relapse and 3 succumbed due to advanced cancer.Conclusion: Primary results showed that GISTs might have different manifestations and incidence in Iran compared to other parts of the world. We hope that this study could serve as a starting point for the better understanding and classification of this disease in Iran and for development of improved management strategies.

Background: GASTROINTESTINAL STROMAL TUMORS (GISTs) constitute the majority of GASTROINTESTINAL mesenchymal TUMORS. They usually express a proto-oncogen protein called CD117 detected by immunohistochemistry. This study investigated the differentiation of GISTs as well as the risk of aggressive behaviors in GISTs from surgically-treated patients in university affiliated hospitals. Methods: The clinicopathologic, histomorphologic and immunohistochemical features of 36 GISTs of patients referring to two large general hospitals in the last 13 years were examined. Results: The GISTs occurred in 36 patients (41.6% male and 58.4% female) aging 15 to 89 years. 50% of the cases were in the stomach, 30% in the small intestine and the remainder in the colon and mesenter. The diameters of TUMORS were 0.7 to 30 cm and mostly (60.6%) more than 5. 85% of tumor cells were spindle, 14% epithelioid, and the remainders were mixed. 36.1% of TUMORS showed mitotic counts > 5/50 HPF and 11.1% less than 5/50HPF. 33.3% of the TUMORS showed necrosis. 8 TUMORS had malignant behavior during 13-yrs follow up. Immunoreactivity for c-kit, SMA, chromogranin, synaptophysin, desmin and S100 were 83.3%, 69.4%, 44.4%, 41.6%, 50% and 0%, respectively. The decreasing rank order of differentiation forms were neural, smooth muscle, dual and null. Most of our TUMORS were in high risk group and most of the high risks were intestinal with neurogenic differentiation. Conclusion: Immunostaining including c-kit is necessary to study the differentiation of GASTROINTESTINAL STROMAL TUMORS.

Background: GASTROINTESTINAL STROMAL TUMORS are the most common mesenchymal tumor originating from the GASTROINTESTINAL tract and have a broad spectrum of clinicopathological features affecting disease management regarding the treatment modalities. Methods: A retrospective study of 49 patients who underwent surgery for GASTROINTESTINAL TUMORS between 2008 and 2016 was conducted. Clinical, pathological, and immunohistochemical features of patients with and without recurrence were statistically analyzed. Results: Twenty-nine (59. 1%) patients had gastric,16 (32. 6%) had small intestinal,3 (6. 1%) had mesenteric,and 1 (2. 2%) had rectal GASTROINTESTINAL STROMAL TUMORS. Microscopic tumor necrosis and tumor ulceration were also significant for disease recurrence (P=0. 005, P=0. 049). High-risk patients according to Miettinen’s Risk Classification were more likely to develop a recurrence (P<0. 001). Additionally, high-grade TUMORS were also a risk factor for recurrence (P<0. 001). Ki-67 levels were available in 40 patients and the mean Ki-67 level was 16. 8 in patients with recurrence, which was a significant risk factor in regression analysis (HR: 1. 24, 95%, CI: 1. 08-1-43). Five-year disease-free survival rates of non-gastric and gastric GASTROINTESTINAL STROMAL TUMORS were 62. 3% and 90%, respectively (P=0. 044). Conclusions: Larger TUMORS and higher mitotic rates are more likely to develop recurrence. High Ki-67 levels were also associated with recurrence.

BACKGROUND: GASTROINTESTINAL STROMAL TUMORS (GIST) are the most common mesenchymal TUMORS of the GASTROINTESTINAL (GI) tract. They are usually C-kit positive and seen slightly more common in men. These TUMORS are seen in the GI tract from the esophagus to the anus with occasional invasion or metastasis.METHODS: In this retrospective study, we evaluated the prevalence of c-kit positive STROMAL TUMORS of the GI tract based on age, site of involvement, size of tumor, local invasion, and Immunohistochemical markers. The study was conducted in Mashhad University of Medical Sciences in Iran during 2003-2012.RESULTS: Of the total 46 patients, 18 (39.1%) were men and 28 (60.9%) were women with a mean age of 58.07 years (range: 18-93). Common sites of tumor were stomach, small intestine, esophagus and rectum, respectively. The number of mitoses per 50 HPF varied between zero and 160 mitoses. Overall, 23 cases had 5 mitoses 50/HPF (50%) and 23 TUMORS expressed <5 mitoses/50 HPF (50%). Local invasion and metastasis were observed in seven cases with extension to liver, pancreas, pregastric tissue, omentum, mesentery and appendix. Positive reaction for CD34, S100, actin and desmin was seen in 47.8%, 13%, 21.7%, and 4.3% of the patients, respectively.CONCLUSION: Most patients were women. The prevalence of TUMORS in the esophagus was higher than the rectum. Invasion and metastasis did not correlate with mitotic rate, site and size of tumor. We suggest evaluation of genetic, racial and geographical or other unknown risk factors.

Background: STROMAL TUMORS of the GASTROINTESTINAL tract (GISTs) are uncommon and the cell of origin is actually mesenchymal. Stemming from smooth muscle, 90% of GISTs, or leiomyomas, are found in the lower two thirds of the esophagus. Typically solitary, multiple TUMORS (leiomyomatosis) are occasionally reported. Remaining intramural during their growth, most of their bulk protrudes toward the esophageal outer wall, with a freely-movable, normal-looking overlying mucosa. In this study, we report a rare case of esophageal leiomyomatosis treated by esophagectomy.Case Report: A 70-year-old man presented with discomfort upon swallowing, dysphagia, nausea, belching and weight loss. After barium swallow, only dilatation of the esophagus from the retained food and saliva was seen. CT scan revealed a 10-cm dilatation of the thoracic esophagus. An endoscopy and upper GI series was performed, but no pathology was found. Esophageal manometry and pH monitoring for gastroesophageal reflux were normal. Upon endoscopic ultrasonography, a thickening of the esophageal wall was identified 20-30 cm from the dental arch. The patient was diagnosed with a GIST, referred to surgeon and a transhiatal esophagectomy was performed. The patient was discharged from the hospital in good condition and has had no problem during the one-year period of follow up.