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Background: Many studies reporting that down-regulation of SOCS6 plays vital roles in promoting progression of malignant tumors have been published. The present study was performed to evaluate whether SOCS6 was significantly associated with prognosis of GIST patients., Methods: Immunohistochemical staining was accomplished to evaluate the expression levels of SOCS6 among GIST patients. The impacts of SOCS6 expression on overall survival (OS) and recurrence-free survival (RFS) of GIST patients were assessed by Cox proportional hazard regression model analysis and Kaplan-Meier curve analysis., Results: It was demonstrated that the expression level of SOCS6 was significantly associated with tumor size (P=0.001). Then according to Kaplan-Meier curve analysis, low expression of SOCS6 was significantly correlated with worse OS and RFS of GIST patients. Ultimately, it was revealed by Cox proportional regression model analysis that low expression of SOCS6 was an independent predictive factor for OS and RFS., Conclusions: Low expression of SOCS6 was an independent prognostic factor for GIST, suggesting its potential as a novel biomarker predicting survival of GIST patients., (© 2021. The Author(s).)

The majority of gastric neoplasms are of epithelial type. Stromal tumours are the next most frequent and are most commonly gastrointestinal stromal tumours, followed by leiomyoma and schwannoma. We present an exceptional case of a patient with a gastrointestinal stromal tumour with suspicion of residual gastric disease, which was diagnosed post-operatively as a schwannoma., (Copyright © 2018 Sociedad Española de Anatomía Patológica. Publicado por Elsevier España, S.L.U. All rights reserved.)

Aberrant alterations of DNA methylation are common events in oncogenesis. The origin of cancer-associated epigenetic defects is of interest for mechanistic understanding of malignant transformation and-in the long run-therapeutic modulation of DNA methylation in a locus-specific manner. Given the ability of certain long noncoding RNAs to operate as an interface between DNA and the epigenetic modification machinery which can interact with DNA methyltransferases, we hypothesized-considering HOTAIR as an example-that this transcript may contribute to gene specificity of DNA methylation. Using gastrointestinal stromal tumors (GISTs, n = 67) as a model, we confirmed upregulation of HOTAIR in tumors with high risk of recurrence and showed high abundance of the transcript in GIST cell lines. HOTAIR knockdown in GIST-T1 cells triggered transcriptional response of genes involved in the organization and disassembly of the extracellular matrix and, notably, induced global locus-specific alterations of DNA methylation patterns. Hypomethylation was induced at a total of 507 CpG sites, whereas 382 CpG dinucleotides underwent gain of methylation upon HOTAIR depletion. Importantly, orchestrated gain or loss of methylation at multiple individual CpG sites was shown for cancer-related DPP4, RASSF1, ALDH1A3, and other targets. Collectively, our data indicate that HOTAIR enables target specificity of DNA methylation in GIST and is capable of dual (hypo- and hypermethylation) regulation by a yet to be defined mechanism. The results further suggest the feasibility of manipulating DNA methylation in a targeted manner and are of interest in the context of epigenetic cancer therapy., (© 2018 Wiley Periodicals, Inc.)

Background: Although the primary malignant spleen tumor is relatively rare, lymphoma is the most common splenic malignancy. It can have quite different clinical manifestations that usually lead to relatively poor outcomes, and thus early and accurate diagnosis are of utmost importance., Case Presentation: The present study reports a case of a 67-year-old female with high fever, abnormal spleen (diagnosed by PET/CT) and no obvious lymph node enlargement. After being subjected to splenectomy, the patient was diagnosed with splenic diffuse large B cell lymphoma coexisting with gastrointestinal stromal tumor in the stomach., Conclusions: To our knowledge, splenic lymphoma accompanied by gastrointestinal stromal tumor in the stomach is rarely reported. This case report discusses the diagnosis and case management of a patient referring to the existing literature.

Objective: To study clinical and pathologic characteristics of leiomyomas of the gastrointestinal tract, and to investigate the distribution characteristics of interstitial cells of Cajal ( ICCs ) in gastrointestinal leiomyomas. Methods: One hundred and forty-seven cases of leiomyomas of gastrointestinal tract were collected at the Second Affiliated Hospital of Zhengzhou University from June 2012 to June 2017. Clinical and pathologic findings were analyzed, combined with immunohistochemistry, Alcian blue-osafranin staining and molecular study. Results: The age of patients ranged from 13-82 years with mean age of 52 years. Male to female ratio was about 1∶2. Histologically, all tumors were composed of ovoid to spindle cells arranged in short intersecting fascicles. All tumors were diffusely and strongly positive for smooth muscle antibodies, desmin and h-caldesmon by immunohistochemical staining. A prominent interspersed subpopulation of elongated/dendritic-like cells with CD117 and DOG1 positivity (accounting for 1% to 30% of all tumor cells) and negative for Alcian blue-osafranin staining was identified in all esophageal leiomyomas, 16 of 20 (80%) gastric leiomyomas and 3 of 12 small bowel leiomyomas, but none in colonic/rectal leiomyomas. Mutational analysis in 16 cases showed absence of mutation in exons 9, 11, 13 or 17 of C-KIT and exons 12 or 18 of PDGFRA. Conclusions: ICCs are identified in esophageal and gastric leiomyomas, as well as in small percentage of intestinal leiomyomas. Such findings may bring significant diagnostic pitfalls for misdiagnosis as gastrointestinal stromal tumor. Careful attention to the distribution of CD117 and DOG1 positive cells and molecular mutation analysis of C-KIT and PDGFRA may be necessary to establish the correct diagnosis.

Importance: Gastrointestinal stromal tumors (GISTs) are life-threatening when metastatic or not amenable to surgical removal. In a few patients with advanced GISTs refractory to imatinib mesylate, treatment with sunitinib malate followed by regorafenib provides tumor control; however, additional active treatments are needed for most patients., Objective: To evaluate the 6-month progression-free survival (PFS), tumor objective response, and overall survival rates in patients with GISTs treated with dasatinib., Design, Setting, and Participants: This single-arm clinical trial used a Bayesian design to enroll patients 13 years or older with measurable imatinib-refractory metastatic GISTs treated at 14 sarcoma referral centers from June 1, 2008, through December 31, 2009. A control group was not included. Patients were followed up for survival for a minimum of 5 years from date of enrollment. Tumor imaging using computed tomography or magnetic resonance imaging was performed every 8 weeks for the first 24 weeks and every 12 weeks thereafter. Tumor response was assessed by local site using the Choi criteria. Treatment was continued until tumor progression, unacceptable toxic effects after reduction in drug dose, or patient or physician decision. Archival tumor tissue was evaluated for expression of the proto-oncogene tyrosine-protein kinase Src (SRC), phosphorylated SRC (pSRC), and succinate dehydrogenase complex iron sulfur subunit B (SDHB) proteins and for mutation in the V-Kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) and platelet-derived growth factor receptor α (PDGFRA) genes. Data analysis was performed from May 19, 2017, through December 20, 2017., Interventions: Dasatinib, 70 mg orally twice daily., Main Outcomes and Measures: The primary end point was the 6-month PFS estimate using greater than 30% as evidence of an active drug and less than 10% as evidence of inactive treatment., Results: In this study, 50 patients were enrolled (median age, 60 years; age range, 19-78 years; 31 [62%] male and 19 [38%] female; 41 [82%] white), and 48 were evaluable for response. The estimated 6-month PFS rate was 29% in the overall population and 50% in a subset of 14 patients with pSRC in GISTs. Objective tumor response was observed in 25%, including 1 patient with an imatinib-resistant mutation in PDGFRA exon 18., Conclusions and Relevance: Dasatinib may have activity in a subset of patients with imatinib-resistant GISTs. Further study is needed to determine whether pSRC is a prognostic biomarker.

Objective: Procedures for diagnosing bone tumors should be rapid and minimally invasive. Thus, cytological examinations are more useful for such purposes than histological examinations. In order to identify cytomorphological findings that could be used to diagnose bone metastasis from gastrointestinal stromal tumors (GIST), previous cases were reviewed., Study Design: Cytological samples of 7 lesions from 4 patients with GIST-derived bone metastasis, which were obtained from 2001 to 2017 at the JFCR Cancer Institute Hospital, were reviewed., Results: The metastasis of GIST to the bone was clinically suspected before the cytological and histological examinations in all cases since they all involved other metastatic lesion(s), and characteristic osteolytic lesions were detected on radiological images. Although various cell shapes were encountered, spindle cell proliferation was seen in all cytological samples. No pleomorphism was apparent. Characteristic nuclear findings were observed. All of the cases could be diagnosed as GIST-derived bone metastasis., Conclusion: GIST-derived bone metastasis can be diagnosed by examining cytological samples., (© 2018 S. Karger AG, Basel.)

Objective: To investigate the clinicopathologic and molecular characteristics, diagnostic, differential diagnostic and prognostic features of malignant gastrointestinal neuroectodermal tumor. Methods: Two cases of malignant gastrointestinal neuroectodermal tumor were retrieved; the clinical and radiologic features, histomorphology, immunophenotype, molecular genetics and prognosis were analyzed and the relevant literature reviewed. Results: Case 1 was a 57-year-old male, presented with recurrent abdominal pain and melena. Pelvic imaging showed a circumscribed thickening of the wall of a small intestinal segment, and a malignant lymphoma was favored. Case 2 was a 24-year-old male, presented with recurrent small intestinal malignancy. Imaging demonstrated multiple masses in the peritoneal and pelvic cavities, and a malignant gastrointestinal stromal tumor with multiple metastases was suspected. Grossly both tumors were located mainly in the muscularis propria of small intestine. Case 1 showed a single 5.5 cm tumor; and case 2 consisted of two tumors measuring 4 cm and 6 cm respectively. Microscopic examination of both tumors showed small round blue, but focally spindled or clear tumor cells in solid pattern. The tumor cells had scanty cytoplasm, indistinctive nucleoli and brisk mitoses. Osteoclast-like giant cells were dispersed within the stroma. In case 1 rosette-like and pseudo-papillary growth patterns were noted, and in case 2 there were variable-sized hemorrhagic cysts. By immunohistochemistry, both tumors showed strong and diffuse expression of SOX10 and S-100, and focal to diffuse expression of neuroendocrine markers (CD56 or synaptophysin). Case 2 exhibited focal reactivity to pan-cytokeratin. Both tumors lacked expression of markers associated with gastrointestinal stromal tumor, smooth muscle tumor, melanoma (HMB45 or Melan A), dendritic cell tumor and Ewing sarcoma. Fluorescence in situ hybridization analysis demonstrated EWSR1 rearrangement in both tumors and the next generation sequencing confirmed EWSR1-ATF1 gene fusion in case 2. At follow-up of 16 months, case 1 was recurrence or metastasis free; whereas case 2 showed multiple recurrences and metastases within 19 months although stable disease was transiently achieved when treated with combinations of multidrug and targeted chemotherapy. Conclusions: Malignant gastrointestinal neuroectodermal tumor is a rare and aggressive soft tissue sarcoma with a predilection for small intestine. It has distinctive morphologic, immunohistochemical and molecular characteristics and needs to be distinguished from other small blue round and spindle cell tumors that occur in the gut. Careful attentions to its characteristic histomorphology with the judicious use of immunohistochemistry and molecular genetics can help to distinguish this tumor from its many mimickers.

Gastrointestinal stromal tumor (GIST), the most common mesenchymal neoplasm of the gastrointestinal tract, exhibits diverse histologic and clinical manifestations. With its putative origin in the gastrointestinal pacemaker cell of Cajal, GIST can arise in association with any portion of the tubular gastrointestinal tract. Morphologically, GISTs are classified as spindled or epithelioid, though each of these subtypes encompasses a broad spectrum of microscopic appearances, many of which mimic other histologic entities. Despite this morphologic ambiguity, the diagnosis of GIST is aided in many cases by immunohistochemical detection of KIT (CD117) or DOG1 expression. The natural history of GIST ranges from that of a tumor cured by surgical resection to that of a locally advanced or even widely metastatic, and ultimately fatal, disease. This clinicopathologic heterogeneity is paralleled by an underlying molecular diversity: the majority of GISTs are associated with spontaneous activating mutations in KIT, PDGFRA, or BRAF, while additional subsets are driven by genetic lesions-often inherited-of NF1 or components of the succinate dehydrogenase enzymatic complex. Specific gene mutations correlate with particular anatomic or morphologic characteristics and, in turn, with distinct clinical behaviors. Therefore, prognostication and treatment are increasingly dictated not only by morphologic clues, but also by accompanying molecular genetic features. In this review, we provide a comprehensive description of the heterogenous molecular underpinnings of GIST, including implications for the practicing pathologist with regard to morphologic identification, immunohistochemical diagnosis, and clinical management.

We report the case of a 60-year-old man with 4 concurrent primary cancers: thyroid papillary carcinoma, esophageal squamous cell carcinoma, lung adenocarcinoma, gastric stromal tumor, and nodular goiter. A minimally invasive McKeown esophagectomy with 3-field lymph node resection played a major role in the diagnosis and resection of all primary tumors in the same sitting. Multiorgan primary cancers are not uncommon but pose challenges in diagnosis and treatment. The mechanism of development is unknown but exposure to the same carcinogens in multiple organs has been implicated.

Gastric neuroendocrine tumors (GNETs) with spindle cell morphology are extremely rare. We present a case of a 49-year-old female patient with a history of systemic lupus erythematosus, Sjogren's syndrome, and gastroesophageal reflux disease. She was initially thought to have a spindle cell gastrointestinal stromal tumor per histological studies of the fundic polypectomy samples. Immunohistochemically, the tumor cells were negative for CD117, and CD34, but positive for chromogranin, synaptophysin, and CD56 with a 6% Ki-67 index, consistent with a spindle cell-type well differentiated neuroendocrine tumor, World Health Organization (WHO) Grade 2. To the best of our knowledge, this is the first case report of a gastric spindle cell neuroendocrine tumor in the English literature., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Most gastrointestinal stromal tumors (GISTs) occur in the tubular gastrointestinal (GI) tract, but some present apparently outside the GI tract. In this study, we analyzed 112 GISTs located in the retroperitoneum. These tumors occurred in 55 women and 57 men with a median age of 65 years (range: 21 to 89 y). On the basis of clinically or histologically detected connections to GI tract, 15 tumors were considered likely of gastric, 9 duodenal, and 13 of small intestinal origin. The remaining cases were categorized by location as peripancreatic (n=25), pelvic (n=11), mesenteric (n=4), and of unspecified/miscellaneous sites (n=35). The tumors varied in size 3 to 35 cm (median, 15 cm) and by mitotic rate per 5 mm, 0 to >100 (median, 10). Histologically the tumors apparently arising outside the GI tract had features of intestinal (n=41) and gastric GISTs (n=25); 9 cases had indeterminate histology. The histologic variants included spindled, epithelioid, vacuolated, nested, and myxoid potentially simulating other tumors such as liposarcoma and solitary fibrous tumor. Most GISTs were KIT-positive (106/112 cases), and the remaining 6 tumors were DOG1/Ano1-positive. Five cases showed focal nuclear positivity for MDM2. KIT mutations were detected in 42/59 cases, and PDGFRA mutations in 4/16 KIT wild-type and 3/5 of the KIT-negative tumors analyzed. One pelvic retroperitoneal GIST was succinate dehydrogenase deficient. All 79 patients were dead at last follow-up with a median survival of 14 months, with few survivals >5 years. Only operable versus inoperable tumor was a statistically favorable factor in univariate analysis (P<0.01). In multivariate analysis, mitotic rate >50/5 mm was significant for a shorter survival (hazard ratio, 5.25; 95% confidence interval, 1.65-16.8; P<0.01). Histologic and clinicopathologic similarity of extragastrointestinal retroperitoneal GISTs with GISTs of GI tract suggests their GI tract origin. Potentially overlapping features between GIST and other retroperitoneal tumors necessitate use of multiple diagnostic markers and molecular genetic studies.

In KIT/PDGFRA wild-type gastrointestinal stromal tumors (wt-GISTs), BRAF mutations are regarded as alternative pathogenic events driving tumorigenesis. In our study, we aimed at analyzing a large cohort (n=444) of GISTs for BRAF mutations using molecular and immunohistochemical methods. More than 3000 GIST samples from caucasian patients were available in our GIST and Sarcoma Registry NRW. Of these, we selected 172 wt-GISTs to evaluate the frequency of BRAF mutations. Furthermore, 272 GISTs with a representative KIT and PDGFRA mutational status were selected. BRAF mutational status was evaluated by high-resolution melting analysis, Sanger sequencing, and VE1 immunohistochemistry. A BRAF mutation (p.V600E) was found in 7 cases (3.9%) of the wt-GIST cohort. In 2 cases, multiple synchronous tumors harbored the same somatic BRAF mutation. VE1 immunohistochemical staining had a sensitivity of 81.8% and a specificity of 97.5% to detect BRAF p.V600E mutations. Analyzing our cases and the cases reported in the literature (n=37), the percentage of intermediate and high-risk BRAF-mutated wt-GISTs (17/31; 54.8%) was comparable to that recorded for large GIST cohorts irrespective of the mutational status. BRAF mutations are rare events in wt-GISTs, and VE1 immunohistochemistry appears to be a valuable pre-screening tool for the detection of BRAF p.V600E mutations. BRAF mutations in GISTs do not seem to have a prognostic value per se. However, as BRAF inhibition represents a therapeutic option to control disease, we suggest the assessment of the BRAF mutational status, especially in the setting of advanced GIST disease., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Malignant gastrointestinal neuroectodermal tumor (GNET) is an extremely rare entity that was first described by Zambrano et al. in 2003 as "Clear cell sarcoma-like tumor of the gastrointestinal tract". It shares some of the histological features of clear cell sarcoma (CCS) but lacks the immunohistochemical reactivity for melanocytic markers. We report a case of GNET that was initially misdiagnosed as gastrointestinal stromal tumor (GIST). Recognizing this entity is important to avoid misdiagnosis., Case Presentation: A case of an 18-year-old male presented with a small intestinal tumor. Histologically it was characterized by polygonal cells arranged in pseudoalveolar pattern and situated in the muscularis propria. Scattered osteoclast-like multinucleated giant cells were also noted. The neoplastic cells were positive for S-100 protein and negative for HMB-45, Melan A, smooth muscle actin, desmin and CD117. EWSR1 gene rearrangement was detected by fluorescence in situ hybridization (FISH) analysis. The patient returned with recurrence after 36 months' management by surgical resection and died one year later., Conclusions: GNET can be mistaken histologically for other non-epithelial gastrointestinal tumors. Awareness of its existence and diagnostic criteria by the pathologist is necessary to avoid misdiagnosis, particularly as GIST, CCS or malignant peripheral nerve sheath tumor (MPNST).

Objective: We aimed to review our archives in order to evaluate both the diagnostic and prognostic significance of DOG1 on gastrointestinal stromal tumors (GISTs), and add further insight about those issues to the current literature including some conflicting results., Material and Method: DOG1 was evaluated in 100 cases of GISTs, immunohistochemically. Immunostaining index was counted for each antibody by using both the intensity and extent of staining. The association between immunostaining index of DOG1 and CD117, CD34, SMA desmin, S-100, and Ki-67 index and clinicopathological features were analyzed., Results: Ninety cases were positive for DOG1, and 89 were positive for CD117. All CD117-negative tumors were positive for DOG1. High-risk group was directly correlated with tumor diameter, cellularity, necrosis, nuclear pleomorphism, mitotic count and Ki-67 index, by univariate analysis. The association between high-risk group and tumor diameter, mitotic count, and Ki-67 index was proved by multivariate analysis. Immunostaining index of DOG1, Ki-67 index, mitotic count, ulceration and hemorrhage were inversely correlated with overall survival by univariate analysis. The adverse impact of DOG1 ISI and mitotic count on overall survival were supported by multivariate analysis., Conclusion: DOG1 positivity was detected in most of GISTs and all in CD117-negative cases as a result underlining its diagnostic utility. Additionally, DOG1 overexpression was related with adverse prognosis. Thus, we suggest that immunostaining index of DOG1 should routinely be used while diagnosing GIST, and DOG1 might be considered as a potential prognostic tool and a target for novel therapies.

Objective: Inhibitor of growth 4 (ING4) is a novel tumor suppressor gene that is reported to be down-regulated in various tumors including gastrointestinal stromal tumors (GISTs) originated from different locations, recently. Herein, we aimed to evaluate ING4 expression and its prognostic significance on gastric GISTs in order to add further data to the current literature., Material and Methods: ING4 was evaluated in samples of gastric GISTs from 62 patients, by immunohistochemistry. The association between ING4 expression and clinicopathological features related with prognosis and overall survival (OS) were analyzed statistically., Results: There was statistically significant inverse correlation between ING4 expression and risk groups according to both NIH and AFIP, Ki67 index, tumor diameter, and mitotic count by univarite analysis (p=0.000, p=0.000, p=0.08, p=0.01, and p=0.028, respectively). The negative association between ING4 expression and risk groups according to both NIH (p=0.002, β=-0.263, t=-3.166) and AFIP (p=0.016, β=-0.244, t=-2.492) was supported by multivariate analysis. There was statistically significant direct correlation between low levels of ING4 expression and shorter OS by univariate (p=0.000) and multivariate analysis (p=0.000, β=0.769, t=9.798), as well as Kaplan-Meier method (p=0.035)., Conclusions: The low ING4 expression level was found to be related with unfavorable prognosis. Thus, we suggest that loss of ING4 expression might play a role in the progression of GISTs and might be used as a potential prognostic tool. Additionally, this is the first study that has evaluated the association of ING4 expression on gastric GISTs, to the best of our knowledge. Therefore, we claim that more comprehensive future studies including higher number of patients and longer follow-up might clarify the potential role of ING4 on pathogenesis and prognosis of GISTs., Key Words: Clinicopathological features, Gastrointestinal stromal tumor, ING4, Immunohistochemistry.

The neural cell adhesion molecule L1 (CD171) is a multidomain type 1 membrane glycoprotein of the immunoglobulin superfamily important in the nervous system development, kidney morphogenesis, and maintenance of the immune system. Recent studies reported CD171 expression being associated with adverse clinical outcome in different types of cancer and there has been a growing interest in targeting this cell membrane molecule on neoplastic cells by chimeric antigen receptor redirected T lymphocytes or specific antibodies. Nevertheless, conflicting results regarding the prognostic value of CD171 expression in renal cell carcinomas and gastrointestinal stromal tumors were published. In this study, CD171 expression was immunohistochemically analyzed in 5155 epithelial, mesenchymal, melanocytic, and lymphohematopoietic tumors to assess its utility in diagnostic pathology and to pinpoint potential targets for CD171-targeting therapy. A newly developed anti-CD171 rabbit monoclonal antibody, clone 014, was selected from the panel of commercially available CD171 antibodies. Immunohistochemistry was performed using Leica Bond Max automation and multitumor blocks containing up to 60 tumor samples. CD171 was constitutively and strongly expressed in neuroectodermal tumors such as schwannoma, neuroblastoma, and paraganglioma, whereas other mesenchymal tumors including schwannoma mimics showed only rarely CD171 positivity. Frequent CD171-expression was also detected in ovarian serous carcinoma, malignant mesothelioma, and testicular embryonal carcinoma. CD171 immunohistochemistry may have some role in immunophenotypic differential diagnosis of neurogenic tumors and pinpointing potential candidates for anti-CD171 therapy. Though, because of its rare expression and lack of predictive value, CD171 is neither a diagnostic nor prognostic marker for gastrointestinal stromal tumors.

Objective: To investigate the clinicopathologic characteristics and therapy of rectal gastrointestinal stromal tumors (GISTs)., Methods: Clinical findings, morphologic features, immunophenotype and prognosis of 53 cases (58 samples) of rectal GISTs were investigated., Results: Thirty-three patients were male and 20 were female. The age of patients ranged from 19 to 81 years, with an average of 49.7 years. The main symptoms included rectal disorders in 29 patients and vaginal mass in 2 patients, while the tumors in 22 patients were found by routine physical examination. Thirty-five primary GISTs were resected completely without preoperative therapy, and thirteen tumors were resected after therapy of imatinib. Five tumors were recurrent. Imatinib therapy in 13 patients led to smaller and softer tumor mass grossly and decreased cellularity and marked degeneration histologically. Of the 35 primary rectal GISTs, there were 17 (48.6%), 6 (17.1%), 0(0), and 12 (34.3%) cases diagnosed as very low risk, low risk, medium risk, and high risk respectively. Eight cases had tumor of 1 cm or less in diameter. In the five recurrent cases, the tumors showed increased cellularity, mitotic figures, and Ki-67 index. Imatinib therapy led to smaller and softer tumor mass grossly and decreased cellularity and marked degeneration histologically. Immunohistochemical stains showed CD117, DOG1, and CD34 positivity, S-100 protein negativity and indefinite SMA stain., Conclusions: Rectal GISTs are rare tumors with a male predominance.Patients without obvious sypmtoms are found by themselves and by routine physical examination. The tumor diameter less than 2 cm is common while larger than 5 cm is few. Diagnosis of rectal GISTs is easily made by biopsy and patients often acquire preoperative therapy for preserving anal sphincter function.

We present the case of a 63-year-old man that was admitted for melena and severe anemia. Upper GI endoscopy and colonoscopy failed to identify the lesion responsible for bleeding, and enteroCT scan was also non-contributive to the diagnosis. Capsule endoscopy indicated possible jejunal bleeding but could not indicate the source of bleeding, recommending anterograde enteroscopy. Single balloon enteroscopy identified a 2 cm submucosal tumour in the distal part of the jejunum, with a macroscopic appearance suggesting a gastrointestinal stromal tumour (GIST). The tumor location was marked using SPOT tattoo and subsequently easily identified by the surgeon and resected via minimally invasive laparoscopic-assisted approach. Histological and immunohistochemical analysis indicated a low risk GIST. The unusual small size of the GIST as a modality of presentation, with digestive bleeding and anemia and the ability to use VCE/enteroscopy to identify and mark the lesion prior to minimally invasive surgery, represent the particularities of the presented case.

Unlabelled: In this article, we reviewed the case of a patient who was object, in 1999, of a published case report of schwannoma of the jejunal wall. Recently, the patient has been referred to our institution for a mass of the stomach identified by upper gastrointestinal endoscopy. The patient underwent a wedge resection of the stomach and a histopathological diagnosis of GIST of the stomach, based on a positive immunohistochemical staining of c-kit and CD34, was made. In consideration of these findings, we performed immunohistochemistry for c-kit and for CD34 on the previous lesion of the jejunal wall, which resulted strongly positive for CD117 and negative for CD34. A new diagnosis of gastrointestinal stromal tumour (GIST) of jejunal wall with moderate risk of progression was made. The lesion was also classified, according to the AJCC Seventh Edition, as a pT3, pN0, Stage II, GIST. This case shows the importance of a reassessment of the diagnosis of mesenchymal neoplasm of the small intestine made before the development of anti-CD117 antibody for a correct prognostic stratification, a better therapeutic management and a close follow-up, if necessary., Key Words: Adjuvant therapy, c-kit, GIST Imatinib.

Gastrointestinal stromal tumors (GISTs) are the most common primary mesenchymal tumors of the digestive tract. GISTs include a group of heterogeneous tumors with different morphology, biologic behavior, and genetic characteristics, so their epidemiology, clinico-pathological features and prognosis is distinct in different countries. The objective of this study is to analyze clinico-pathological characteristics and prognostic factors of GISTs among Chinese population. We investigated 112 GIST patients were diagnosed between July 2008 and January 2013 at the First Affiliated Hospital of Guangxi Medical University. Histologic evaluation and immunohistochemistry analysis was performed on paraffin-embedded tissue from the 112 GISTs. Overall survival analysis was carried out using the Kaplan-Meier method and the log-rank test. Multivariate analysis was performed according to Cox's proportional hazards model. Three and 5-year OS rates were 71.4 and 58.6% respectively. Univariate analysis showed that the following factors were significant in predicting OS: tumor site, tumor size, metastasis, resection margin status, cell type, invasion of adjacent organ, invasion of smooth muscle, mitotic rate, P53 and adjuvant therapy with imatinib (P<0.05). Multivariate analysis showed that tumor size, metastasis, resection margin status, mitotic rate, P53 and adjuvant therapy with imatinib were independent prognostic factors associated with OS. This may aid in the prediction of clinical evolution and guide treatments in patients with GIST in China.

Objective: Some authors suggest common origin of gastrointestinal stromal tumors from stem cells, which may show diverse differentiation. There are reports in which cells morphologically identical to the interstitial cells of Cajal are found in deep leiomyomas. The aim of this study was to demonstrate CD117 positive cells in superficial gastrointestinal (GI) leiomyomas and to find other cells that would suggest diverse differentiation in histologically typical leiomyoma., Materials and Methods: We analyzed 8 cases of superficial leiomyomas and one deep leiomyoma, received in our institutions as endoscopically or surgically obtained material. The tumor sections were immunohistochemicaly stained with CD117, CD34, NF, S100, αSMA, desmin, caldesmon and mast cell antigen., Results: All leiomyomas showed diffuse positivity for αSMA, caldesmon and desmin. All of them had CD117 and CD34 positive cells morphologically identical to the interstitial cells of Cajal between smooth muscle fibers, 5 had S-100 and NF positive cells and 2 showed positivity for GFAP. The cells were found in different quantity; they were usually diffusely scattered through the tumors without predilection site, forming small groups in some areas., Conclusion: CD177, CD34, S-100 and NF positive cells are present in superficial leiomyomas and they may suggest common origin of GI 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.

Collision tumors of the stomach are rare. We report on a case of a collision tumor consisting of a gastrointestinal stromal tumor (GIST) and an inflammatory myofibroblastic tumor (IMT) of the stomach in a 16-year-old female. A polypoid mass located in the distal body of the stomach was observed on abdominal computed tomography. Laparoscopic wedge resection of the stomach and 4d lymph node biopsy was performed. On gross examination, a protruding submucosal mass, measuring 4 × 3.5 × 2.5 cm in size, was detected. Histological examination showed two distinct GIST and IMT component presenting a collision tumor. The small nodular area, composed of CD117-positive spindle cells, was typical of GIST, and the adjacent larger area, composed of myofibroblastic spindle cells with prominent chronic inflammatory cells infiltrate, mainly lymphocytes and plasma cells, had a characteristic appearance of IMT. The 4d lymph node showed metastatic inflammatory myofibroblastic tumor. To the best of our knowledge, this is the first case of a collision tumor consisting of a GIST and an IMT arising in the stomach.

Introduction: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Numerous studies have reported the association between GIST and other neoplasms., Objectives: The aim of this study was to investigate the possible association between GIST and other tumors in a genetically isolated population., Methods: A retrospective study was conducted of patients with GIST between 2002 and 2009 at our center. Epidemiological, pathological and family data in patients with GIST alone (group A) were compared with those in patients with GIST associated with other neoplasms (group B). A possible common genetic mechanism was investigated between GIST and associated malignancies by testing the detection of the immunohistochemical marker, CD117, in all tumors., Results: Twenty-two patients with GIST were identified, 10 in group A (45%) and 12 in group B (55%). In group B, the associated tumor was malignant in 6 patients (50%) and benign in another 6 (50%). Of the 22 patients with GIST, 8 (36%) had a family history of malignancies. Of these 8 patients, 7 (87.5%) were in group B (p=0.03) and 3 (37.5%) showed the same pathological type of neoplasm as their relatives. All GIST were positive for CD117 whereas associated malignancies were negative for this marker., Conclusion: We did not find immunohistochemical positivity for CD117 in malignancies associated with GIST. Given the special characteristics of the study population, the association between GIST and associated malignancies may be incidental., (Copyright © 2015 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved.)

Gastrointestinal stromal tumors (GISTs) were originally thought to harbor either KIT or platelet-derived growth factor receptor A (PDGFRA) mutations only. However, more recent discoveries have highlighted additional, less common oncogenic driver mutations including NF1, BRAF, and succinate dehydrogenase (SDH) mutations. Genotyping GISTs has become more important since not all genotypes respond equally to FDA-approved tyrosine kinase inhibitors. GIST is a paradigm for personalized cancer therapy. Recent studies demonstrate how immunohistochemistry can be used both to diagnose GIST and to screen for specific mutations. DOG1 is particularly useful in the diagnosis of KIT-negative GIST, including tumors with PDGFRA mutations, which can also potentially be identified by immunohistochemistry for PDGFRA. SDHB immunohistochemistry is useful in characterizing GISTs with SDHA-D mutations, whereas SDHA immunohistochemistry is able to identify SDHA mutant GISTs., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: To assess the influence of SLIT and NTRK-like family member 3 (SLITRK3) on the prognosis of gastrointestinal stromal tumor (GIST) and determine whether SLITRK3 can help improve current risk stratification systems., Methods: We hypothesized that SLITRK3 could be used as a prognostic molecular biomarker for GIST. 35 fresh tumor samples and 417 paraffin-embedded specimens from GIST patients were utilized. SLITRK3 mRNA expression in GIST tumor tissue was detected by real-time polymerase chain reaction, and SLITRK3 protein levels were estimated by immunohistochemistry. The correlation of SLITRK3 expression with various tumor clinicopathological characteristics and follow-up data were analyzed., Results: GIST tumors had high expression of SLITRK3 compared with adjacent normal tissues and the expression level gradually increased with risk grade. SLITRK3 protein expression was closely associated with gastrointestinal bleeding, tumor site, tumor size, mitotic index, and National Institutes of Health (NIH) classification. Survival analysis showed that SLITRK3 expression was closely correlated with overall survival and disease-free survival of GIST patients. Multivariate analysis also identified SLITRK3 expression, mitotic index, and NIH stage as significant risk factors of GIST recurrence., Conclusion: SLITRK3 expression is a highly significant predictor of GIST recurrence and metastasis. Combinations of SLITRK3 and NIH stage have strong predictive and prognostic value, and are feasible markers for clinical practice in gastrointestinal stromal tumor.

Aim: To evaluate the correlation between the immunoexpression of angiogenic markers [CD31, CD105 and vascular endothelial growth factor (VEGF)], proliferative index (Ki67), and prognosis of patients with gastrointestinal stromal tumors (GIST)., Methods: This is a retrospective study of 54 GIST cases. Medical records were searched to obtain the GIST patients' demographic and clinical data, and paraffin-embedded blocks of tumor samples were retrieved from the hospital archives to conduct a new immunohistochemical evaluation. The tumor samples of GIST patients were subject to immunohistochemical evaluation for endoglin (CD105), CD31, VEGF, and Ki67 expression. The CD105 and CD31 intratumoral microvascular density (IMVD) was measured using automated analysis. We determined the correlation between the immunoexpression of CD105, CD31, VEGF, Ki67 and prognosis. In addition, we conducted a cutoff analysis using the receiver-operating characteristic curve. VEGF positivity was classified as either null/weak or strong. Ki67 was evaluated using a cutoff of 5% positive cells. The prognosis was classified as good (patient alive without recurrence) or poor (patient with recurrence/death)., Results: The distribution of tumor sites among the 54 analyzed samples was as follows: 27 (50%) in the stomach, 20 (37.1%) in the small intestine, 6 (11.1%) in the colon, and 1 (1.8%) in the esophagus. The size of the tumors ranged from 2 to 33 cm (median: 8 cm); in 12 cases (22.2%), the tumor was below 5 cm at the largest diameter, but in 42 cases (77.7%), the tumor was larger than 5 cm. The means of CD105 and CD31 were significantly higher in the group with poor prognosis (P < 0.001). The cut-off values of CD105 (> 1.2%) and CD31 (> 2.5%) in the receiver-operating characteristic curve were related to a poorer prognosis. Cases with a better prognosis showed significantly null/weak staining for VEGF (P < 0.001). Ki-67 expression of ≥ 5% was strongly correlated with a worse prognosis (P < 0.001). In the multivariate analysis, CD105 was the variable that most strongly correlated with prognosis., Conclusion: The IMVD cutoff values for the angiogenic markers CD105 and CD31, may be prognostic factors for GIST, in addition to VEGF and Ki67.

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract that are most commonly found in the stomach. Although GISTs can spread to the liver and peritoneum, metastasis to the skeletal muscle is very rare and only four cases have previously been reported. These cases involved concurrent skeletal metastases of primary GISTs or liver metastases. Here, we report the first case of a distant recurrence in the brachialis muscle after complete remission of an extra-luminal gastric GIST following a wedge resection of the stomach, omental excision, and adjuvant imatinib therapy for one year. Ten months after therapy completion, the patient presented with swelling and tenderness in the left arm. Magnetic resonance imaging revealed a large mass in the brachialis muscle, which showed positivity for c-kit and CD34 upon pathologic examination. This is the first reported case of a solitary distant recurrence of a GIST in the muscle after complete remission had been achieved.

Activating mutations of platelet-derived growth factor receptor α (PDGFRA) are detected in a significant proportion of gastrointestinal stromal tumors (GISTs), in addition to the more frequent mutation in c-kit. GISTs with PDGFRA mutations have been found to have several characteristic morphological features, sometimes allowing to discriminate them from GISTs with c-kit mutations. Among these, epithelioid morphology in tumor cells and tumor-infiltrating mast cells are powerful predictors of PDGFRA mutations. Although myxoid stroma by itself is not so much a reliable predictor of PDGFRA mutation, myxoid stroma in conjunction with epithelioid morphology in tumor cells is a powerful predictor of mutations in this gene. GISTs showing either weak or negative immunoreactivity for c-kit and epithelioid cells with myxoid stroma are called myxoid epithelioid GISTs, which typically show PDGFRA mutation. Herein, we presented a case of a 59-year-old woman with myxoid epithelioid GIST of the stomach. A unique finding in this case was eosinophil infiltration, probably more numerous than mast cells; mast cell infiltration is known to be usually found in myxoid epithelioid GIST. The existence of a similar mechanism in eosinophil and mast cell recruitment via tumor-producing stem cell factor is speculated. Mutational analyses revealed a PDGFRA exon 18 mutation: D842&#95;H845del, D846N. Combined deletion and substitution mutation has been reported in rare instances, but to the best of our knowledge, D846N has not been documented.

A patient who was diagnosed as rectal polyps in the local hospital went to our hospital for surgical treatment. Abdominal CT demonstrated a large irregular extra-luminal tumor of at least 5 cm cross-section on the ventral side of the lower rectal wall. Intraoperatively, a large irregular extra-luminal tumor (about 5×4.5×4 cm) was found. Anterior resection with end colostomy and rectal stump (Hartmann's procedure) was performed. Postoperative histological examination showed simultaneous development of rectal GIST and polyps.

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract, but they represent less than 3% of all gastrointestinal tract malignancies. This is a detailed case study of a 52-year-old male patient treated for very uncommon histological subtype of gastric GIST with atypical clinical presentation, asymptomatic progress and late diagnosis. The resected tumour, giant in diameters, was confirmed to represent the most rare histopathologic subtype of GISTs - sarcomatoid epithelioid GIST. We report this case and review the literature with a special focus on pathomorphological evaluation, biological aggressiveness and prognostic factors. To our knowledge this is the first report of giant GIST of very uncommon sarcomatoid epithelioid subtype. It is concluded that clinicians should pay attention to the fact that initial diagnosis may be delayed due to mildly asymptomatic and non-specific clinical presentation. Asymptomatic tumours diagnosed at a late stage, which is often the case, can be large on presentation. Prognosis for patients diagnosed with GIST depend on tumour size, mitotic rate, histopathologic subtype and tumour location. That is why early diagnosis and R0 resection, which is usually feasible and safe even in giant gastric sarcomatoid epithelioid subtype of GISTs, are the key factors for further treatment and good prognosis.

The coincidence of GIST and other gastric malignancies are documented well but arising GIST from congenital anomalies is still rarity in literature. To date, only a few papers have been concerned on the possibility of arising neoplasms from duplication cyst of gastrointestinal tract. There, are dominating usual cancers, neuroendocrine cancers or lymphomas but GIST has been noted only once. Here, we report a case of 73 years old female-patient with typical gastric stromal tumor comprised centrally locked an incomplete duplication cyst.

A 67-year-old female presented with a primary hepatic gastrointestinal stromal tumor that was detected by computed tomography and diagnosed based on histopathological and genetic analyses. The tumor was microscopically composed of spindle cells and epithelioid cells, and immunohistochemistry results showed positive staining for CD117 and CD34 expression. A genetic analysis revealed a heterozygous point mutation and deletion in exon 11 of c-KIT. After an R0 resection, imatinib mesylate was administered for 1 year until its use was discontinued due to severe side effects. Two years after the original operation, the tumor recurred in the residual liver and was completely resected again. Imatinib mesylate was administered for 2 years until it was replaced by sunitinib malate because of disease progression. The patient has survived for 53 mo after undergoing a sequential therapy consisting of surgical excision, imatinib and sunitinib.

Aim: To investigate the clinicopathologic features of patients with extra-gastrointestinal stromal tumors (EGISTs) in South Korea., Methods: A total of 51 patients with an EGIST were identified. The clinicopathologic features, including sex, age, location, tumor size, histology, mitotic rate, immunohistochemical features, genetic status and survival data, were analyzed., Results: The median age was 55 years (range: 29-80 years), and male:female ratio was 1:1.04. The most common site was in the mesentery (n = 15) followed by the retroperitoneum (n = 13) and omentum (n = 8). The median tumor size was 9.0 cm (range: 2.6-30.0 cm) and the median mitotic rate was 5.0/50HPF. (1/50 - 185/50). KIT was analyzed in 16, which revealed 10 cases with wild-type KIT and 6 cases with an exon 11 mutation. Among 51 patients, 31 patients had undergone surgery, and 10 had unresectable disease and had taken palliative imatinib, which resulted in 22.7 mo of progression-free survival. Of the patients who had undergone surgery, 18 did not take adjuvant imatinib, and 8 of these were categorized as "high risk" according to the risk criteria. However, the relapse-free survival was not different (P = 0.157) between two groups., Conclusion: Because the biologic behaviors of GISTs differ according to the location of the tumor, a more stratified strategy is required for managing EGISTs including incorporation of molecular features.

The new World Health Organization (WHO) classification of soft tissue tumours was published in 2013, 11years after the previous edition. This new classification includes several changes: newly included sections (gastrointestinal stromal tumors…), newly recognized entities (pseudomiogenic haemangioendothelioma, haemosiderotic fibrolipomatous tumour…), and new genetic and molecular data leading to better understanding and definition of tumours, and are useful as diagnostic tools. This brief review summarizes changes in this new edition of the WHO classification of tumours of soft tissue., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background/aims: To review our treatment experience of gastrointestinal stromal tumors (GISTs) of the upper gastrointestinal tract and identify the prognostic factors that influence tumor recurrence., Methodology: Data of 46 consecutive patients with upper GI GISTs who underwent surgery from 1988 to 2011 were reviewed. The overall and disease-free survival rates and influence of clinicopathologic variables on disease-free survival rate were evaluated., Results: The median age was 64 years (range, 20-86 years). R0 resections were performed in 43 (93.5%) patients. With a median follow-up time of 33 months (1-275 months), there were 5 (10.9%) recurrences and 2 mortalities in the high-risk group. The overall survival and recurrence-free survival rates at 5 years were 92.1% and 84.6%, respectively. Male gender, tumor size of >10 cm, high numbers of mitotic figures, R1 resection, high risk according to the Joensuu criteria, and a Ki-67 index of >10% were associated with a poor prognosis., Conclusions: Surgical resection of low- and intermediate-risk GISTs has excellent results. High counts of mitotic figures, male gender, incomplete resection, large tumor size, and a high Ki-67 index are associated with a poor prognosis.

Although the stomach is the most common location for gastrointestinal stromal tumor (GIST) with co-primary tumors, the synchronous appearance of a poorly differentiated neuroendocrine carcinoma (NEC) and GIST in the stomach is extremely rare. To the best of our knowledge, this is the first case of gastric GIST coexisting with gastric NEC to be reported in the literature. The current study reports the case of a 71-year-old male with gastric poorly differentiated NEC and GIST discovered incidentally during surgical treatment of the NEC. Immunohistochemistry analysis showed that the NEC tumor cells were positive for CK (cytokeratin), CD57, synaptophysin, chromogranin, CD117 (KIT protein), Dog-1 (discovered on GIST-1 protein) and CD34. The synchronous GIST immunophenotype showed positivity for CD117, Dog-1 and CD34 (100%), whereas staining for CK, SMA, desmin and S100 was negative. Ki-67 labeling of proliferating cells was 90% in NEC and 1% in GIST. An accurate diagnosis was confirmed by immunohistochemical findings. Furthermore, genetic analysis using PCR direct sequencing identified no mutations in the KIT (exons 9, 11, 13 and 17) and PDGFRA (exons 12 and 18) genes. The patient developed lymph node metastases and underwent cisplatin-based chemotherapy after the operation. This is the first documented case of synchronous gastric GIST and NEC with the examination of protein expression and gene mutations in KIT and PDGFRA, which will help to further understand the etiology and pathogenesis of NEC coexisting with GIST in a gastric location.

Background and Aims: There is no evidence of postoperative metastasis of gastric gastrointestinal stromal tumors (GISTs) smaller than 2 cm. The aim of this study was to evaluate the clinical usefulness of endoscopic ultrasound guided fine needle aspiration (EUS-FNA) for gastric subepithelial lesions (SELs) smaller than 2 cm., Patients and Methods: Using a prospectively maintained EUS-FNA database, 90 consecutive EUS-FNAs of gastric hypoechoic solid SELs smaller than 2 cm diagnosed by EUS were evaluated retrospectively. The reference standards for the final diagnosis were surgery (n=44) and/or clinical follow-up (n=46) using esophagogastroduodenoscopy (EGD), CT, and/or ultrasonography (US). Additionally, immunophenotyping of specimens obtained by EUS-FNA and surgical resection specimens were compared., Results: The diagnostic rate of EUS-FNA for gastric hypoechoic solid SELs smaller than 2 cm was 73% (66/90). Histological diagnosis of EUS-FNA showed 47 (52%) malignant SELs (44 GISTs, 1 glomus tumor, 1 SEL like cancer, and 1 malignant lymphoma), 19 (21%) benign SELs (14 leiomyomas, 4 ectopic pancreas, and 1 neurinoma), and 24 (27%) indeterminate SELs. In 44 surgically resected cases, the diagnostic accuracy of EUS-FNA using immunohistochemical analysis was 98% (43/44). There were no complications. Appropriate management was performed in 65 out of 66 SELs (98%) diagnosed by definitive EUS-FNA. After surgery, there was no recurrence of malignant SELs., Conclusions: EUS-FNA is an accurate and safe method in the pre-therapeutic diagnosis of gastric SELs smaller than 2 cm. EUS-FNA for gastric SELs smaller than 2 cm is a promising way to permit early management of patients with gastric SELs including GIST.

Primary malignant tumors of the small intestine are rare, comprising less than 2% of all gastrointestinal tumors. An 85-year-old woman was admitted with fever of 40 °C and marked abdominal distension. Her medical history was unremarkable, but blood examination showed elevated inflammatory markers. Abdominal computed tomography showed a giant tumor with central necrosis, extending from the epigastrium to the pelvic cavity. Giant gastrointestinal stromal tumor of the small intestine communicating with the gastrointestinal tract or with superimposed infection was suspected. Because no improvement occurred in response to antibiotics, surgery was performed. Laparotomy revealed giant hemorrhagic tumor adherent to the small intestine and occupying the peritoneal cavity. The giant tumor was a solid tumor weighing 3490 g, measuring 24 cm × 17.5 cm × 18 cm and showing marked necrosis. Histologically, the tumor comprised spindle-shaped cells with anaplastic large nuclei. Immunohistochemical studies showed tumor cells positive for vimentin, CD31, and factor VIII-related antigen, but negative for c-kit and CD34. Angiosarcoma was diagnosed. Although no postoperative complications occurred, the patient experienced enlargement of multiple metastatic tumors in the abdominal cavity and died 42 d postoperatively. The prognosis of small intestinal angiosarcoma is very poor, even after volume-reducing palliative surgery.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract. Less than 1% occurs in the esophagus. Surgery is the primary treatment for patients with GISTs. We report a 29-year-old male was admitted after the detection of a posterior mediastinal mass during work-up with routine examination. He did not have any disease-related symptoms. The physical examination was unremarkable. Chest computed tomographic scan, the barium esophagogram and endoscopic esophageal ultrasound showed benign neoplasm. The patient was performed an enucleation surgery through the right posterolateral thoracotomy. The pathology revealed a 13.0 cm × 12.0 cm × 5.0 cm mass. The tumor was CD117 (C-kit), PDGFRA and DOG1 positive. These findings were consistent with a GIST of the esophagus. So the diagnosis of GIST of esophagus was confirmed. The pathological diagnosis of low grade of GIST of esophagus was confirmed. The patient has no evidence of recurrence and is in good clinical conditions up-to date, five years after surgery.

Atonal homolog 1 (Atoh1) is crucial to the differentiation of many cell types and participates in tumorigenesis and progression. However, the expression of Atoh1 in gastrointestinal stromal tumors (GIST) and its relationship to clinical characteristics of this disease remain poorly understood. In this study, immunohistochemical analysis using tissue microarray (TMA) was employed to evaluate the expression of Atoh1 in GIST and the correlation between Atoh1 expression and clinicopathological features of GIST as well as patient outcome. High Atoh1 cytoplasmic expression was observed in 77.22% of patients with GIST, which was related to the mitotic index (P = 0.010) and AFIP-Miettinen risk classification (P = 0.045). High Atoh1 nuclear expression was seen in 69.49% of cases, which was associated with mitotic index (P = 0.003) and AFIP-Miettinen risk classification (P = 0.001). The Kaplan-Meier method and log-rank test indicated that high Atoh1 cytoplasmic expression, high Atoh1 nuclear expression, small tumor diameter, low mitotic index and TNM stage significantly correlated with improved survival of GIST patients. Overall, the data suggest that Atoh1 high expression correlates with a good prognosis and it may serve as a favorable prognostic factor for GIST. These results also support a role for Atoh1 as a tumor suppressor gene in GIST.

Aim: To assess the effectiveness of endoscopic full-thickness resection (EFR) and laparoscopic surgery in the treatment of gastric stromal tumors arising from the muscularis propria., Methods: Out of 62 gastric stromal tumors arising from the muscularis propria, each > 1.5 cm in diameter, 32 were removed by EFR, and 30 were removed by laparoscopic surgery. The tumor expression of CD34, CD117, Dog-1, S-100, and SMA was assessed immunohistochemically. The operative time, complete resection rate, length of hospital stay, incidence of complications, and recurrence rate were compared between the two groups. Continuous data were compared using independent samples t-tests, and categorical data were compared using χ (2) tests., Results: The 32 gastric stromal tumors treated by EFR and the 30 treated by laparoscopic surgery showed similar operative time [20-155 min (mean, 78.5 ± 30.1 min) vs 50-120 min (mean, 80.9 ± 46.7 min), P > 0.05], complete resection rate (100% vs 93.3%, P > 0.05), and length of hospital stay [4-10 d (mean, 5.9 ± 1.4 d) vs 4-19 d (mean, 8.9 ± 3.2 d), P >0.05]. None of the patients treated by EFR experienced complications, whereas two patients treated by laparoscopy required a conversion to laparotomy, and one patient had postoperative gastroparesis. No recurrences were observed in either group. Immunohistochemical staining showed that of the 62 gastric stromal tumors diagnosed by gastroscopy and endoscopic ultrasound, six were leiomyomas (SMA-positive), one was a schwannoglioma (S-100 positive), and the remaining 55 were stromal tumors., Conclusion: Some gastric stromal tumors arising from the muscularis propria can be completely removed by EFR. EFR could likely replace surgical or laparoscopic procedures for the removal of gastric stromal tumors.