Gastrointestinal stromal tumors: a review of case reports, diagnosis, treatment, and future directions

Huge Gastrointestinal Stromal Tumor (GIST) in Upper Gastrointestinal Masquerade Anaemia

Gastrointestinal stromal tumor (GIST) represents a rare neoplasm affecting the gastrointestinal (GI) tract and is classified as a common nonepithelial tumor within the GI tract. It originates from the interstitial cells of Cajal, and GIST typically manifests with symptoms such as abdominal pain, weight loss, and gastrointestinal bleeding. This case involves a 33-year-old male who presented with GI bleeding symptoms after eight months of treatment for anemia. Oesophagogastroduodenoscopy (OGDS) revealed a singular ulcerated mass measuring 4x4cm while a computed tomography (CT) scan identified a large fundal exophytic component extending from the gastroesophageal junction to the stomach. Subsequently, the patient underwent a laparotomy and proximal gastrectomy with Roux-en-Y reconstruction, which revealed a 12x10 cm tumor located at the fundus of the stomach. This report aims to underscore the potential for misdiagnosis in the initial presentation of GIST, emphasizing the importance of raising clinical awareness in such cases.

A Case of Gastrointestinal Stromal Tumour (GIST) in the Duodenum in a Young Adult

Gastrointestinal stromal tumours (GISTs) are rare gastrointestinal (GI) malignancies, but the most prevalent mesenchymal tumours of the GI tract arise from the interstitial cells of Cajal. They account for 1-3% of all GI malignancies, and only 3-5% of all cases of GIST are located at the duodenal. We present a case of a young adult who presented to the ED with symptoms of GI bleeding.

A Unique Case of Mesenteric Gastrointestinal Stromal Tumor Presenting as an Acute Abdomen

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the digestive tract and arise from the interstitial cells of Cajal in the mesenteric plexus. These tumors can originate in any part of the GI tract; however, a higher burden has been observed in the stomach and small intestines. Mesenteric GISTs are exceedingly rare, with unique clinicopathological features and a poorer prognosis. Herein, we describe a unique case of a 66-year-old female with a remote history of appendectomy who presented to the emergency room complaining of severe abdominal pain and vomiting. On imaging, the patient was found to have a large inflammatory mass associated with small bowel loops, and the pathology confirmed a mesenteric GIST. The tumor was resected, and the genomic test results confirmed the KIT (exon 11) mutation. Although the tumor had a low mitotic rate, the tumor was large enough to warrant the initiation of adjuvant imatinib mesylate for 36 months with regular bloodwork and imaging.

Gastrointestinal Stromal Tumor Masquerading As Acute Decompensated Heart Failure: A Challenging Diagnosis

Gastrointestinal stromal tumors (GISTs) are rare lesions of the gastrointestinal tract that have a strong predisposition to the stomach and small intestine. We present a case of an 89-year-old female who initially presented to the emergency room with signs and symptoms of acute decompensated heart failure (HF) and was later discovered to have a 23-centimeter GIST in her abdominal cavity. This case emphasizes the implications of large intraperitoneal neoplasms and the unique constellation of symptoms they may present with.

An unusual and life-threatening presentation of a large GIST

Introduction

Case presentation

Clinical discussion

Conclusion

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Although an acute presentation of GIST is rare, it must be recognised early to prevent further morbidity and mortality.

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The overlap between the symptoms of GIST and other GI disorders could lead to an uncertain diagnosis and thus unfavourable outcome.

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Imaging modalities along with immunohistochemical studies have eased the diagnosis of GIST

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The characteristics of the tumor largely influence the treatment pathway.

Effects of Endoscopic Submucosal Excavation With Non-Submucosal Injection on Stromal Tumors in Stomach

Background and Aim

Endoscopic submucosal excavation (ESE) is commonly used to treat gastrointestinal stromal tumors (GISTs), especially for tumor sizes within 2 cm; compared with the conventical ESE, the efficacy and safety of the no-submucosal injection (NSI) ESE remains unclear. The aim of this study was to assess the clinical efficacy and safety of NSI-ESE for gastric stromal tumors.

Methods

ESE was performed in 102 patients at our hospital between January 2018 and January 2020, and the clinical features, surgical outcomes, complications, cost of performance, pathological diagnosis, and risk classification were evaluated.

Results

All tumors were completely resected by endoscopic resection (ER), with a complete resection rate of 100%. It was achieved by ESE/EFTR (endoscopic full-thickness resection) in 49 cases with submucosal injection, and by ESE/EFTR in 53 cases with NSI-ESE. The mean surgical time in cases with submucosal injection was 25.86 ± 4.45 min, compared to the cases without submucosal injection (17.23 ± 3.47 min), and the difference was significant (p < 0.001); the exposure time of tumor, the time of complete excavation of tumor, procedure cost, and hospital stay in the NSI-ESE group were all lower than those cases with submucosal injection (p < 0.05). In the risk classification, 95 (93.1%) cases had a very low risk, 4 (4.0%) cases had a low risk, and 2 (2.0%) cases had a high risk. No recurrence or metastasis was observed during the follow-up period of 18 ± 6 months (range: 13–25 months).

Conclusions

NSI-ESE is a feasible, effective, and safe treatment for gastric GISTs; compared to the conventional ESE, NSI-ESE has the following advantages: it decreases procedure time, it lowers the risk of perforation, and it is cost-effective.

Predictors of the difficulty for endoscopic resection of gastric gastrointestinal stromal tumor and follow-up data

BACKGROUND AND AIM

Gastrointestinal stromal tumors (GISTs) are among the most common submucosal tumors in the stomach that require therapeutic intervention. We aim to identify the predictors of technical difficulty during endoscopic resection of gastric GIST and to investigate follow-up outcomes.

METHODS

Patients with gastric GISTs were reviewed from June 2009 to June 2020 at Zhongshan Hospital. Clinical and pathological features, endoscopic procedure information, and follow-up data were collected and analyzed. A nomogram was developed and validated internally and externally.

RESULTS

A total of 628 GISTs were finally analyzed. The difficulty was experienced in 66 cases. GISTs size (2-3 cm: OR 2.431 P = 0.018 and > 3 cm: OR 9.765 P < 0.001), invasion depth beyond submucosal (MP: OR 2.280, P = 0.038 and MP-ex: OR 4.295, P = 0.002), and lack of experience (OR 2.075, P = 0.016) were independent risk factors of difficulty. The nomogram prediction model showed a bias-corrected C-index value of 0.778 and acquired an area under curve (AUC) of 0.756 on the external validation cohort. At the cut-off of 0.15, the nomogram's negative predictive value (NPV) and accuracy (ACC) were 94.9% and 79.8% in identifying non-difficult GISTs. Follow-up results showed that only five GIST patients had local recurrence after endoscopic resection.

CONCLUSIONS

Tumor size, invasion depth, and endoscopists' experience were risk factors for the difficulty of endoscopic GIST resection. Our nomogram provided a valuable tool for screening non-difficult GIST resection.

Refractory hypoglycaemia in a localised gastrointestinal stromal tumour: Case report

Introduction

GIST and NICTH are mesenchymal in origin however there are very few reports of GIST associated with NICTH which is a para neoplastic syndrome, generally diagnosed when a tumour induced hypoglycaemia is noted.

Case presentation

A 46 years old female with prime complain of awareness of a mass in the upper abdomen was admitted for evaluation and further management. Detailed investigation revealed the mass to be gastrointestinal stromal tumour. On the day of admission patient was found to be hypoglycaemic which didn't resolve even after 10% glucose infusion. A growth hormone releasing peptide-2 (GHRP-2) assay was carried out which showed an excessive reaction of basal growth hormone however corticotropin releasing hormone (CRH) tests were within normal limits. She was suspected to be Non Islet cell tumour hypoglycaemia (NICTH) and hypoglycaemia resolved upon administering dexamethasone. Later she underwent chemotherapy and surgical resection after which her blood sugar levels were within normal limits.

Discussion

Expression of big IGF-II on the surface of GIST be it metastatic or nonmetastatic can cause refractory hypoglycaemia and can be fatal if left untreated.

Conclusion

Clinicians should be aware of refractory hypoglycaemia in patients with large GIST's as glucocorticoid therapy may prove to be extremely useful and lifesaving even before considering any forms of definitive management of the tumour.

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Localised GISTS may present with refractory hypoglycaemia.

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If not diagnosed due to clinical vague nature, it can be fatal.

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It responds very well to steroid treatment and can prevent a potentially fatal condition.

Bromodomain and extraterminal domain inhibitor enhances the antitumor effect of imatinib in gastrointestinal stromal tumours

In gastrointestinal stromal tumours (GISTs), the function of bromodomain-containing 4 (BRD4) remains underexplored. BRD4 mRNA abundance was quantified in GISTs. In the current study, we investigated the role of BRD4 in GISTs. Our results show a significant enhancement in BRD4 mRNA and a shift from very low-risk/low-risk to high-risk levels as per NCCN specifications. Overexpression of BRD4 correlated with unfavourable genotype, nongastric location, enhanced risk and decreased disease-free survival, which were predicted independently. Knockout of BRD4 in vitro suppressed KIT expression, which led to inactivation of the KIT/PI3K/AKT/mTOR pathway, impeded migration and cell growth and made the resistant GIST cells sensitive to imatinib. The expression of KIT was repressed by a BRD4 inhibitor JQ1, which also induced myristoylated-AKT-suppressible caspases 3 and 9 activities, induced LC3-II, exhibited dose-dependent therapeutic synergy with imatinib and attenuated the activation of the PI3K/AKT/mTOR pathway. In comparison with their single therapy, the combination of JQ1/imatinib more efficiently suppressed the growth of xenografts and exhibited a reduction in KIT phosphorylation, a decrease in Ki-67 and in the levels of phosphorylated PI3K/AKT/mTOR and enhanced TUNEL staining. Thus, we characterized the biological, prognostic and therapeutic implications of overexpressed BRD4 in GIST and observed that JQ1 suppresses KIT transactivation and nullifies the activation of PI3K/AKT/mTOR, providing a potential strategy for treating imatinib-resistant GIST through dual blockade of KIT and BRD4.

Endoscopic Removal of Gastrointestinal Stromal Tumors in the Stomach: A Single-Center Experience

BACKGROUND AND AIMS

Endoscopic removal of GISTs (gastrointestinal stromal tumors) is recently recognized, but less is known about its efficacy and safety. This study is aimed at assessing the feasibility, clinical efficacy, and safety of the endoscopic removal of gastric GISTs.

PATIENTS AND METHODS

Endoscopic removal (ER) of GISTs was performed in 134 patients at our hospital between January 2015 and January 2019. The clinical features, surgical outcomes, complications, pathological diagnosis, and risk classification were evaluated retrospectively.

RESULTS

ER was successful in 131 cases (98%), including 58 by ESD (endoscopic submucosal dissection), 43 by ESE (endoscopic submucosal excavation), 25 by EFTR (endoscopic full-thickness resection), and 5 by STER (submucosal tunneling endoscopic resection). In addition, GISTs of two cases were resected using LECS (laparoscopic and luminal endoscopic cooperative surgery) for the extraluminal and intraluminal growth pattern. The average tumor size was 1.89 ± 1.25 cm (range: 0.5-6.0 cm). Of these patients, 26 cases had a large tumor size (range: 2.0-6.0 cm), and endoscopic removal was successful in all of them. During the procedure, endoclips were used to close the perforation in all cases, without conversion to open surgery. The average length of hospital stay was 5.50 ± 2.15 days (range: 3-10 days). In the risk classification, 106 (79.7%) were of a very low risk, 25 (18.8%) of a low risk, and 2 (1.5%) of a moderate risk. The moderate-risk cases were treated with imatinib mesylate after ER. No recurrence or metastasis was observed during the follow-up period of 23 ± 8 months (range: 3-48 months).

CONCLUSIONS

The endoscopic treatment is feasible, effective, and safe for gastric GISTs, and individualized choice of approaches is recommended for GISTs.

Gastric Schwannoma: A Case Report and Review of the Literature for Gastric Submucosal Masses Distinction

Schwannomas origin from Schwann cells sheath and generally are benign, slow-growing, and asymptomatic neoplasms which frequently appear in the head and neck. Although gastrointestinal schwannoma is really rare, the most affected organ in GI system is the stomach. Gastric schwannoma forms 0.2% of all gastric tumors. This neoplasm is always detected as a submucosal mass, the same as other gastrointestinal stromal tumors. Although these tumors have almost the same presentations, they are completely different at therapeutic options and prognoses. Hence, it is important to distinguish them apart and make an accurate diagnosis to optimize treatment outcomes. Herein, we report a case of 28-year-old woman with frequent vomiting and abdominal pain caused by 5 × 6 cm schwannoma in the antrum of the stomach. This is a rare case of gastric outlet obstruction due to a massive schwannoma. In addition, all other probable submucosal masses will be discussed at different aspects.

Lack of microsatellite instability in gastrointestinal stromal tumors

The microsatellite instability (MSI) phenotype may constitute an important biomarker for patient response to immunotherapy, particularly to anti-programmed death-1 inhibitors. MSI is a type of genomic instability caused by a defect in DNA mismatch repair (MMR) proteins, which is present mainly in colorectal cancer and its hereditary form, hereditary nonpolyposis colorectal cancer. Gastrointestinal stromal tumor (GIST) development is associated with activating mutations of KIT proto-oncogene receptor tyrosine kinase (KIT) or platelet-derived growth factor receptor α (PDGFRA), which are oncogenes that predict the response to imatinib mesylate. In addition to KIT/PDGFRA mutations, other molecular alterations are important in GIST development. In GISTs, the characterization of the MSI phenotype is scarce and the results are not consensual. The present study aimed to assess MSI in a series of 79 GISTs. The evaluation of MSI was performed by pentaplex polymerase chain reaction comprising five markers, followed by capillary electrophoresis. The expression of MMR proteins was evaluated by immunohistochemistry. Regarding the KIT/PDGFRA/B-Raf proto-oncogene, serine/threonine kinase molecular profile of the 79 GISTs, 83.6% of the tumors possessed KIT mutations, 10.1% had PDGFRA mutations and 6.3% were triple wild-type. The mutated-PDGFRA cases were associated with gastric location and a lower mitotic index compared with KIT-mutated and wild-types, and these patients were more likely to be alive and without cancer. MSI analysis identified 4 cases with instability in one marker, however, additional evaluation of normal tissue and immunohistochemical staining of MMR proteins confirmed their microsatellite-stable nature. The results of the present study indicated that MSI is not involved in GIST tumorigenesis and, therefore, cannot serve as a biomarker to immunotherapy response in GIST.

Primary Extragastrointestinal Stromal Tumours in the Hepatobiliary Tree and Telocytes

The first decade of the twenty-first century witnessed the presence and light microscopic, immunophenotypic, and ultrastructural characterization of interstitial Cajal-like cells (coined as 'telocytes') in virtually every extragastrointestinal site of the human body by Laurentiu M. Popescu and his co-workers. Not surprisingly, stromal tumours, immunophenotypically similar to that of telocytes [CD117 (c-KIT) +/CD34 +], have also been sporadically reported outside the tubular gut (so-called extragastrointestinal stromal tumours, EGISTs), including the gall bladder, liver, and pancreas. A meticulous literature search from January 2000 to November 2015 have found 9 such case reports of EGISTs in the gall bladder, 16 in the liver, and 31 occurring in the pancreas. The site wise mean age at presentation for these tumours were reported to be 62.2 ± 16.6, 50.9 ± 20.1, and 55.3 ± 14.3 years, respectively. Six of nine EGISTs in the gall bladder were associated with gallstones. On pathological evaluation, these tumours exhibited prominent spindled cell morphology and consistent expression of CD117/c-KIT and CD34 on immunohistochemistry and variable expression of vimentin and α-smooth muscle actin. The biological behaviour of hepatic and pancreatic lesions was favourable compared to that in the gall bladder, following definitive surgery with or without imatinib therapy. While the exact pathophysiologic role played by telocytes in various organs is yet to be fully elucidated, there seems to be a direct link between these enigmatic stromal cells and pathogenesis of gallstones and origin of EGISTs, and a hope for targeted therapies. Furthermore, the possible role of telocytes in hepatic regeneration and liver fibrosis opens a new dimension for futuristic research.

KTN0158, a Humanized Anti-KIT Monoclonal Antibody, Demonstrates Biologic Activity against both Normal and Malignant Canine Mast Cells

Purpose: KTN0158 is a novel anti-KIT antibody that potently inhibits wild-type and mutant KIT. This study evaluated the safety, biologic activity, and pharmacokinetic/pharmacodynamics profile of KTN0158 in dogs with spontaneous mast cell tumors (MCT) as a prelude to human clinical applications.Experimental Design: Cell proliferation, KIT phosphorylation, and mast cell degranulation were evaluated in vitro KTN0158 was administered to 4 research dogs to assess clinical effects and cutaneous mast cell numbers. Thirteen dogs with spontaneous MCT were enrolled into a prospective phase I dose-escalating open-label clinical study of KTN0158 evaluating 3 dose levels and 2 schedules and with weekly assessments for response and clinical toxicities.Results: KTN0158 was a potent inhibitor of human and dog KIT activation and blocked mast cell degranulation in vitro In dogs, KTN0158 was well tolerated and reduced cutaneous mast cell numbers in a dose-dependent manner. Clinical benefit of KTN0158 administration in dogs with MCT (n = 5 partial response; n = 7 stable disease) was observed regardless of KIT mutation status, and decreased KIT phosphorylation was demonstrated in tumor samples. Histopathology after study completion demonstrated an absence of neoplastic cells in the primary tumors and/or metastatic lymph nodes from 4 dogs. Reversible hematologic and biochemical adverse events were observed at doses of 10 and 30 mg/kg. The MTD was established as 10 mg/kg.Conclusions: KTN0158 inhibits KIT phosphorylation, demonstrates an acceptable safety profile in dogs, and provides objective responses in canine MCT patients with and without activating KIT mutations, supporting future clinical evaluation of KTN0158 in people. Clin Cancer Res; 23(10); 2565-74. ©2016 AACR.

A Probabilistic Boolean Network Approach for the Analysis of Cancer-Specific Signalling: A Case Study of Deregulated PDGF Signalling in GIST

BACKGROUND

Signal transduction networks are increasingly studied with mathematical modelling approaches while each of them is suited for a particular problem. For the contextualisation and analysis of signalling networks with steady-state protein data, we identified probabilistic Boolean network (PBN) as a promising framework which could capture quantitative changes of molecular changes at steady-state with a minimal parameterisation.

RESULTS AND CONCLUSION

In our case study, we successfully applied the PBN approach to model and analyse the deregulated Platelet-Derived Growth Factor (PDGF) signalling pathway in Gastrointestinal Stromal Tumour (GIST). We experimentally determined a rich and accurate dataset of steady-state profiles of selected downstream kinases of PDGF-receptor-alpha mutants in combination with inhibitor treatments. Applying the tool optPBN, we fitted a literature-derived candidate network model to the training dataset consisting of single perturbation conditions. Model analysis suggested several important crosstalk interactions. The validity of these predictions was further investigated experimentally pointing to relevant ongoing crosstalk from PI3K to MAPK signalling in tumour cells. The refined model was evaluated with a validation dataset comprising multiple perturbation conditions. The model thereby showed excellent performance allowing to quantitatively predict the combinatorial responses from the individual treatment results in this cancer setting. The established optPBN pipeline is also widely applicable to gain a better understanding of other signalling networks at steady-state in a context-specific fashion.

Ki67 as a prognostic factor for long-term outcome following surgery in gastrointestinal stromal tumors

OBJECTIVE

This study aimed to examine the value of Ki67 expression along with other potential prognostic factors for predicting overall survival and disease-free survival in patients with gastrointestinal stromal tumors who underwent curative resection.

PATIENTS AND METHODS

Sixty-eight histologically confirmed and operated patients with gastrointestinal stromal tumors were included. Clinical and follow-up data were retrieved from medical records and patients were contacted at the end of the study. The effects of certain clinical and histopathological parameters on survival outcomes were examined.

RESULTS

Sixty-eight patients were followed for a mean duration of follow-up of 2923.3 patient-months. Twelve deaths (17.6%), seven metastasis (10.3%), and two local recurrences (2.9%) occurred. Overall survival was 102.5 months [95% confidence interval (CI), 88.3-116.8] and disease-free survival was 91.8 months (95% CI, 76.5-107.2). Multivariate analyses identified a high Ki67 index (≥ 10%) as an independent predictor of both poor overall survival (hazard ratio, 4.8; 95% CI 1.2-19.2; P=0.027) and poor disease-free survival (hazard ratio, 15.3; 95% CI, 4.7-50.2).

CONCLUSION

A high Ki67 expression seems to be a useful prognostic factor that would aid in predicting disease course in gastrointestinal stromal tumors. These findings deserve further investigation in larger studies.

Expression of CD117, DOG-1, and IGF-1R in gastrointestinal stromal tumours - an analysis of 70 cases from 2004 to 2010

Introduction

Determination of the type of mutations in gastrointestinal stromal tumours (GIST) plays a major role in assessing the risk of progression of the disease, and also allows determination of the clinical management and treatment. More accurate GIST diagnosis is possible by using simultaneously various types of antibodies to immunohistochemistry methods in routine procedures.

Aim

To evaluate the expression of CD117, DOG-1, and IGF-1R in patients with gastrointestinal stromal tumours, and analysis of the impact of the examined protein expression on patient survival with emphasis on specific recognition and prognostication of these tumours.

Material and methods

The protein expression was analyzed in 70 patients who had undergone surgical treatment for mesenchymal tumours of the gastrointestinal tract, using the immunohistochemical method.

Results

Positive expression of CD117, DOG-1, and IGF1R included 95.71%, 88.57% and 11.43% of study GISTs, respectively. Statistical analysis showed positive significant correlation between DOG-1 expression and histological type of tumour (p = 0.024). Analysis of overall survival curves of 70 GIST patients according to expression of CD117, DOG-1, and IGF1R did not show a tendency towards longer survival of patients with positive expression (p > 0.05).

Conclusions

Predictive factors determining the survival time of patients are strongly associated with morphological features of tumours. A thorough analysis of each case plays a key role in predicting survival time of patients and may be a clue in targeting the therapeutic procedure.

Presence of PDGFRA and DOG1 mutations in gastrointestinal stromal tumors among Chinese population

Approximately 15% of gastrointestinal stromal tumors (GIST) do not express KIT mutations and of these about 5 to 7% harbor mutations in PDGFRA. DOG1 was specifically expressed in GISTs. These cases require special attention for PDGFRA and DOG1 mutational status. Hundred cases of GIST were diagnosed between August 2007 and October 2012 at the First Affiliated Hospital of Guangxi Medical University. DNA from tumor tissues and normal adjacent tissues was isolated and amplified for the 22 exons of PDGFRA and 26 exons of DOG1. Each PCR product was sequenced. Amino acid sequences were inferred from DNA and aligned to GenBank reference sequences to determine the position and type of mutations. Overall, 16.0% of the samples had a mutation in PDGFRA, and GISTs with mutations in the DOG1 gene were not found. Of the mutations detected, they were in PDGFRA exon 18 (8 cases, 8%), PDGFRA exon 12 (5 cases, 5%), PDGFRA exon 14 (1 cases, 1.0%), PDGFRA exon 11 (1 cases, 1.0%), and PDGFRA exon 8 (1 cases, 1.0%). Of these, Y392S, L521P and T632K mutant occurred in PDGFRA exon 8, exon 11 and exon 14, respectively. The mutation of PDGFRA has been considered as another causative genetic event as PDGFRA mutations were found in most GISTs lacking a KIT mutation. PDGFRA mutations occurred preferentially in exon 18 and exon 12. Mutations occurring in PDGFRA exon 8 (Y392S), exon 11 (L521P) and exon 14 (T632K) also were first identified. The over-expression of DOG1 was not related to DOG1 gene mutation.

Gastrointestinal stromal tumor of the adrenal gland:a case report and review of the literature

Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal (GI) tract. The occurrence of these neoplasms ectopically outside the GI tract is extremely uncommon. Only one case of primary adrenal GIST has been reported in the literature. In this account, we report a second case of primary adrenal GIST in a 34-year-old male who presented with a 5-week history of gradually progressive left flank pain and early satiety. Whole-body positron emission tomography (PET)/computed tomography (CT) scan showed a 14 × 11 cm hypermetabolic (18)fluorodeoxyglucose (FDG)-avid mass lesion involving the left adrenal gland and dorsal part of the left hemi-diaphragm. Biopsy of the lesion revealed tumor cells that are immunoreactive to CD-117 and CD-34 and negative to CD-31, S-100, cytokeratin, desmin, and vimentin, features characteristic of GIST. The patient was given imatinib, which drastically decreased his complaints with almost complete resolution of the tumor on his last follow-up radiographic images. Primary left adrenal GIST is an extremely rare neoplasm and can be confused with GISTs arising from the greater curvature of the stomach. Imatinib therapy is optimal in the management of these tumors.

Gastroduodenal intussusception due to pedunculated polypoid gastrointestinal stromal tumour (gist ): a rare case

Gastrointestinal stromal tumours (GISTs) account for less than 3% of all gastrointestinal tract tumours and 5.7% of all sarcomas, and the majority of these tumours are gastric in origin. Patients commonly present with gastrointestinal bleeding or abdominal pain with 10-30% of patients presenting with symptoms of gastrointestinal obstruction. We report a rare case clinically presenting as gastric outlet obstruction, gastroscopy suspecting it to be organo-axial gastric volvulus, CECT(Contrast Enhanced Computerised Tomography) suggesting features of gastric malignancy (leiomyosarcoma) keeping the possibility of differential diagnosis of GIST. Eventually on exploratory laparotomy we discovered gastric outlet obstruction due to transpylorically herniated pedunculated polypoid GIST leading to gastroduodenal inussusception.

A Pancreatic Head Tumor Arising as a Duodenal GIST: A Case Report and Review of the Literature

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors of the gastrointestinal tract that originate from the intestinal cells of Cajal (ICC) (Fletcher et al., 2002). Only a few cases have been described with extragastrointestinal stromal tumors (Kim et al., 2012; Soufi et al., 2013; Meng et al., 2011). They are often diagnosed as a pancreatic head tumor as they are very difficult to relate to the duodenum with CT, MRI, or ultrasound. We present a case of a sixty-four-year-old woman who presented with abdominal pain and cardialgia for a follow-up examination after breast cancer surgery. On laparotomy there was a 3 × 5 cm hypervascular mass arising from the pancreatic head with macroscopically no attachment to the duodenum. The patient underwent pancreatoduodenectomy (PD) modified after Traverso-Longmire, histopathology proved a duodenal GIST. This case proves that duodenal GISTs can grow invasively into the pancreas and appear as solid pancreas head tumor; therefore, these tumors should be included into differential diagnosis.

Pfetin as a risk factor of recurrence in gastrointestinal stromal tumors

Background. Despite complete resection of gastrointestinal stromal tumors (GIST), recurrent and/or metastatic disease occurs, often depending on the grade of malignancy. As such, markers are needed that accurately predict patients at high risk for recurrence. Previously our group reported Pfetin as a prognostic biomarker for GIST. In order to create an approach for predicting risk of recurrence, we incorporated Pfetin expression with clinicopathological data to produce a predictive model. Object. Forty-five patients with localized primary GIST were treated with complete gross surgical resection surgically at our institution between 1995 and 2010 were included. The majority of tumors originated in the stomach (38 cases), as well as small intestine (6 cases) and rectum (1 case). Method. (1) We performed retrospective analysis of the connection between Pfetin expression, clinicopathological data, and incidences of recurrence, using bivariate and multivariate analyses. (2) The reactivity of the monoclonal antibody against Pfetin was examined by immunohistochemistry. Pfetin. We have reported Pfetin, identified microarray technology, and compared between statistically different GISTs for good and poor prognoses and for prognostic marker. Results. There were 7 cases of recurrences. (1) By univariate analysis, tumor size, mitoses, exposure to abdominal cavity, and complete tumor removal predicted risk of recurrence. (2) Pfetin-negative cases were significantly related to recurrence (P = 0.002). Conclusions. This analysis demonstrates that lack of Pfetin expression is an additional predictor of recurrence in resected GIST. Further study may determine the role of this variable added to the current predictive model for selection of adjuvant therapy.

Colonic gastrointestinal stromal tumor resulting in recurrent colic and hematochezia in a warmblood gelding

A 14-year-old Trakehner gelding was evaluated for recurrent colic, with episodes occurring over 1 year. Signs were consistent with intermittent ascending colon obstruction and hematochezia. Necropsy examination revealed an ulcerated mass extending into the lumen of the right dorsal ascending colon. Gross and histologic appearance and immunoreactivity to c-kit (CD117), desmin, vimentin, and smooth muscle actin, were consistent with a diagnosis of gastrointestinal stromal tumor.

Phase II study of cediranib in patients with advanced gastrointestinal stromal tumors or soft-tissue sarcoma

PURPOSE

Cediranib is a potent VEGF signaling inhibitor with activity against all three VEGF receptors and KIT. This phase II study evaluated the antitumor activity of cediranib in patients with metastatic gastrointestinal stromal tumor (GIST) resistant/intolerant to imatinib, or metastatic soft-tissue sarcomas (STS; ClinicalTrials.gov, NCT00385203).

EXPERIMENTAL DESIGN

Patients received cediranib 45 mg/day. Primary objective was to determine the antitumor activity of cediranib according to changes in 2[18F]fluoro-2-deoxy-D-glucose positron emission tomography ((18)FDG-PET) tumor uptake in patients with GIST using maximum standardized uptake values (SUVmax). Secondary objectives included objective tumor response and tolerability in patients with GIST/STS.

RESULTS

Thirty-four of 36 enrolled patients were treated (GIST n = 24; STS n = 10). At day 29, five patients had confirmed decreases in SUVmax (≥10% from day 8) and two had confirmed partial metabolic responses (≥25% decrease), but arithmetic mean percentage changes in SUVmax, averaged across the cohort, were not significant at day 8 [6.8%; 95% confidence interval (CI), 19.95-33.54) or day 29 (4.6%; 95% CI, 8.05-17.34). Eleven patients with GIST achieved a best objective tumor response of stable disease; eight achieved stable disease ≥16 weeks. In patients with STS, four of six with alveolar soft-part sarcoma (ASPS) achieved confirmed and durable partial responses. The commonest adverse events were diarrhea (85%), fatigue (74%), and hypertension (68%).

CONCLUSIONS

In patients progressing on imatinib/sunitinib, cediranib 45 mg/day demonstrated evidence of activity by (18)FDG-PET, but did not reduce average SUVmax. Evidence of antitumor activity was seen in ASPS.

Primary gastrointestinal stromal tumor of the prostate: A case report and literature review

Extragastrointestinal stromal tumors (EGISTs) are relatively rare soft tissue neoplasms arising from the extra gastrointestinal tract. The current study presents a case of primary EGIST of the prostate observed in a 55-year-old male. Imaging studies showed a 10×10.5×9.5-cm prostate mass. On histological observation, the mass was separated from the rectum serosa and exhibited a high mitotic count (8/50 high-power fields). The results of immunohistochemical staining showed positive immunoreactivity for cluster of differentiation (CD)117 (c-kit), CD34 and DOG1 in the tumor. On mutation analysis, loss of heterozygosity of the c-kit gene was observed in the prostatic EGIST; however, the platelet-derived growth factor receptor-α (PDGFRA) gene was considered to be normal. Therefore, as EGIST of the prostate is rare, there is a requirement for the confirmation of the diagnosis to be based on immunohistochemistry and mutation analysis (of c-kit and PDGFRA).

Multifocal small bowel stromal tumours presenting with peritonitis in an HIV positive patient

INTRODUCTION

The most common mesenchymal tumour of the gastrointestinal tract is stromal tumours (GISTs). Symptomatic GISTs can present with complications such as haemorrhage, obstruction and perforation. Complete surgical resection with negative margins is the mainstay of treatment but may be imprudent on emergent occasion. Tyrosine-kinase inhibitors (TKIs) have been revolutionary in the treatment of GISTs and have resulted in improved outcomes.

PRESENTATION OF CASE

A 41 year old HIV positive male presented with an acute history of abdominal pain and obstructive symptoms. Clinical examination revealed sepsis and peritonitis. One of the several small bowel tumours discovered at exploratory laparotomy was necrotic and perforated. The perforated tumour alone was resected and a small bowel internal hernia reduced. The patient made an uneventful recovery and will be considered for TKI therapy with a view to later re-operation.

DISCUSSION

GISTs very rarely perforate. The pathophysiology of stromal tumour necrosis is poorly understood. Multifocality and small bowel location are poor prognosticators and may occur in the setting of familial GISTs, specific syndromes and sporadic cases. There is no established association between HIV and GISTs.

CONCLUSION

Perforation occurs infrequently in ≤8% of symptomatic cases and poses increased risk of local recurrence. The surgical management of perforation takes precedence in an emergency. The surgeon must however take cognisance of the adherence to ideal oncologic principles where feasible. TKI therapy is invaluable if a re-exploration is to be later considered.

Large cystic-based gastrointestinal stromal tumor: A case report

A 60-year-old male with increasing abdominal distension was admitted to The Fifth Affiliated Hospital of Guangzhou Medical University (Guangzhou, China). The abdominal sonogram exhibited a huge abdominal cystic-based mass with solid components in the left upper quadrant. A contrast-enhanced computed tomography scan of the abdomen revealed a large heterogeneous cystic solid tumor, but the source of the tumor could not be determined. The laparotomy demonstrated a huge cystic-based tumor with an integrated cystic wall, arising from the posterior wall of the gastric body. Multiple septa and ~3,500 ml of yellowish fluid were found in the cystic cavity. Pathological analysis showed that the tumor contained a mixture of polygonal and spindle cells. Immunohistochemical study indicated that the tumor cells were positive for CD117 and CD34. The final diagnosis was gastric gastrointestinal stromal tumor. The patient recovered well and no recurrence or metastasis was identified following a 12-month follow-up.

Perforation as a rare presentation of gastric gastrointestinal stromal tumours: a case report and review of the literature

INTRODUCTION

Gastrointestinal stromal tumours (GISTs) are the most common connective tissue neoplasms of the gastrointestinal tract, the most common clinical presentation of which is with abdominal pain or gastrointestinal bleeding.

METHODS

We describe a case of a perforated gastric GIST as well as reviewing the relevant published literature.

RESULTS

A 51-year-old woman presented to the acute assessment unit with a 1-day history of severe epigastric pain on a background of longstanding reflux symptoms. Radiological investigation demonstrated a perforated mass in the gastric antrum and the patient subsequently underwent an emergency distal gastrectomy. She recovered well postoperatively and was discharged home. Her condition remains stable six months following surgery. Histological analysis revealed the perforated lesion to be a GIST. A PubMed search suggests that this is the first English report to describe a perforated gastric GIST. Six further published reports (written in English or with an English abstract) describing the presentation of small bowel GISTs with perforation are reviewed.

CONCLUSIONS

We present the first English report of a perforated gastric GIST. More common presentations include abdominal pain and gastrointestinal bleeding. Although rare, GISTs should be considered in the differential diagnoses of perforated gastrointestinal masses.

Imatinib responsiveness in canine mast cell tumors carrying novel mutations of c-KIT exon 11

In 2 individual cases of canine mast cell tumors, we identified 2 novel c-KIT mutations in exon 11: a 9-base pair (bp) deletion (c.1663-1671del) and a point mutation (c.1676T>A). The 9-bp deletion mutation caused a loss of 3 amino acids, corresponding to p.Gln555_Lys557del, and the point mutation resulted in the substitution of valine by aspartic acid (p.Val559Asp) in the juxtamembrane domain of the protein. Imatinib mesylate, a therapeutic agent for canine mast cell tumors, was used to treat both tumors. Complete remission was achieved at 33 and 14 days after administration, respectively. However, in both cases, the therapeutic response subsequently tapered with the duration of remission lasting 66 and 255 days, respectively. Although these 2 novel c-KIT mutations in exon 11 were not confirmed to be gain-of-function mutations, a further study may help clarify relevance between mutations identified in this report and responsiveness.

Management of gastric polyps: an endoscopy-based approach

The endoscopic finding of a gastric polyp and the histopathologic report that follows may leave clinicians with questions that have not been addressed in formal guidelines: do all polyps need to be excised, or can they just be sampled for biopsy? If so, which ones and how many should be sampled? What follow-up evaluation is needed, if any? This review relies on the existing literature and our collective experience to provide practical answers to these questions. Fundic gland polyps, now the most frequent gastric polyps in Western countries because of widespread use of proton pump inhibitors, and hyperplastic polyps, the second most common polyps notable for their association with gastritis and their low but important potential for harboring dysplastic or neoplastic foci, are discussed in greater detail. Adenomas have had their name changed to raised intraepithelial neoplasia and are decreasing in parallel with Helicobacter pylori infection; however, they do retain their importance as harbingers of gastric cancer, particularly in East Asia. Gastrointestinal stromal tumors have low incidence and no known associations, but their malignant potential is high; early diagnosis and proper management are crucial. Although rare and benign, inflammatory fibroid polyps need to recognized, particularly by pathologists, to avoid misdiagnosis. Gastric neuroendocrine tumors (carcinoids) are important because of their association with either atrophic gastritis or the multiple endocrine neoplasia syndromes; those that do not arise in these backgrounds have high malignant potential and require aggressive management. The review concludes with some practical suggestions on how to approach gastric polyps detected at endoscopy.

Epigenetics in gastrointestinal stromal tumors: clinical implications and potential therapeutic perspectives

Gastrointestinal stromal tumors (GIST) represent the most common mesenchymal neoplasms affecting the gastrointestinal tract. Activating mutations in either the KIT or PDGFRa gene are the principal oncogenic triggers with the former accounting for more than 80 % of cases. In the small subset of GIST that are wild type for both the aforementioned changes, other germline or somatic mutations have been identified. GIST exhibit a highly variable clinical behavior and the main prognostic determinants are tumor size, mitotic rate, and location. It is, however, strongly believed that, beyond classic genetics, additional epigenetic phenomena such as DNA hypomethylation and hypermethylation, microRNA alterations, and chromatin modifications underlie GIST tumorigenesis and influence the clinical course and response to standard treatment. This review aims to illuminate current advances in terms of epigenetics in GIST, as well as possible implications in prognosis and therapeutics.

Surgical treatment of GIST--an institutional experience of a high-volume center

BACKGROUND

Discovery of the molecular pathogenesis of Gastrointestinal stromal tumors led to the development of targeted therapies, revolutionizing their treatment. However, surgery is still the mainstay of GIST therapy and the only chance for cure.

AIM

Here we present a single institutional consecutive case series of 159 GIST-patients.

METHODS AND PATIENTS

A total of 159 GIST-patients who underwent resection between 1994 and 2011 were reviewed for clinicopathohistological data, informations on surgical and medical therapy and further follow-up, outcome and survival data.

RESULTS

Laparoscopic (25.2%) and open (71.1%) GIST surgery achieved complete resection rates of 97.5% and 85.2%, whereas 44.4% of incomplete and 6.6% of complete resected patients died from GIST. Compared to open surgery laparoscopy significantly reduced duration of operation (183.4 vs. 130.6 min), length of hospitalization (16.1 vs. 8.3 d) and morbidity (23% vs. 7.5%). Mean survival time was 3.7 ± 2.7 years (R0: 5.1 a and R1: 2.6 a) and the mean overall survival was 4.5 ± 3.8 years.

CONCLUSION

Complete surgical resection is the primary goal and laparoscopy can be performed safely in a subset of GIST-patients with potential perioperative advantages. Although not proven by the present study the authors assume that multimodal GIST-treatment, as performed in reference-centers, is required for advanced or high risk disease. Our data suggest the potential for minimally invasive GIST resection to achieving comparable oncological outcomes as after open surgery while providing low morbidity rates.

Upregulated ZO-1 correlates with favorable survival of gastrointestinal stromal tumor

Zonula occludens-1 (ZO-1) is a membrane-scaffolding protein that plays an important role in maintaining tight-junction integrity, which is disrupted in many invasive cancers and intestinal diseases. However, the expression of ZO-1 in gastrointestinal stromal tumor (GIST) and its relationship with clinical characteristics of this disease remain poorly understood. In this study, immunohistochemical analysis using tissue microarray was employed to evaluate the expression of ZO-1 in GIST and to investigate the relationship between its expression and GIST prognosis. High ZO-1 expression was displayed in 71.8 % of GIST patients, which was related to tumor diameter (p < 0.05). The Kaplan-Meier method and log-rank test indicated that high ZO-1 expression, small tumor diameter, tumor position in the esophagus, and a borderline-to-intermediate tumor grade displayed significant correlations with longer survival of GIST patients. The data suggest that ZO-1 expression is correlated with malignant phenotypes of GIST and it may serve as a favorable prognostic factor for GIST. These results also support a role for ZO-1 as a tumor-suppressor gene in GIST.

Gastrointestinal stromal tumor mesenchymal neoplasms: the offspring that choose the wrong path

Gastrointestinal stromal tumors (GISTs) are relatively rare neoplasms of the gastrointestinal tract originating from the pluripotential mesenchymal stem cells, which differentiate into interstitial Cajal cells. They are usually located in the upper gastrointestinal track. These tumors are typically defined by the expression of c-KIT (CD117) and CD34 proteins in the tumor cells. A small percentage of these tumors is negative for c-KIT. The neoplasms are positive for platelet-derived growth factor α (PDGFα) mutations. In addition to PDGFRα mutations, wild-type c-KIT mutations can also be present. The therapeutic approach to locally developed gastrointestinal stromal tumors is surgical resection, either with open or laparoscopic surgery. In case of systemic disease, molecular pharmacologic agents such as imatinib and sunitinib are used for treatment. These agents block the signaling pathways of neoplastic-cell tyrosine kinases, interfering in their proliferation and causing apoptosis.

Primary gastrointestinal stromal tumors: Current advances in diagnostic biomarkers, prognostic factors and management of its duodenal location

Gastrointestinal stromal tumors (GIST) constitute 1-3% of all gastrointestinal malignancies and is the most common mesenchymal tumor of the gastrointestinal tract. Although GIST were first described in the literature in the year 1941, important advances of kit mutation and tyrosine kinase inhibitors were not made to understand and manage GIST until the last decade. Here current advances in research of possible cellular origin, diagnostic biomarkers and prognostic factors of primary GIST are reviewed, and the management of primary duodenal GIST is focused on due to its specific location. It is possible that personalized assessment and therapy will turn out to be another milestone for primary GIST.

Non-Hodgkin lymphoma and GIST: molecular pathways and clinical expressions

We report the case of a 64-year-old woman with a gastrointestinal stromal tumor and a diffuse large cell lymphoma. For this case, we conducted a literature review in an attempt to correlate these two neoplasms on a molecular basis. Diffuse large cell lymphoma is a subtype of non-Hodgkin lymphomas. The etiologic factor of these lymphomas is considered to be the mutations or allelic losses of the TP53 tumor suppressor gene and the overexpression of the bcl-2 oncogene. Gastrointestinal stromal tumors are mesenchymal tumors, which are typically defined by the expression of c-KIT (CD117) and CD34 genes in the tumor cells. Although there are references to dispersants in the literature about patients with both non-Hodgkin lymphoma and gastrointestinal stromal tumors, there is no common molecular pathway between these two diseases. In conclusion, there is no indication that these two neoplasms are relevant on a molecular basis.