Immunohistochemical spectrum of GISTs at different sites and their differential diagnosis with a reference to CD117 (KIT)

Esophageal schwannoma: Case report and epidemiological, clinical, surgical and immunopathological analysis

INTRODUCTION

Schwannoma is a tumor of the peripheral nervous system originated in the Schwann cells of the neural sheath.

PRESENTATION OF CASE

A 43-years-old male complained of odynophagia, dysphagia and hemoptysis. The upper gastrointestinal endoscopy showed a smooth elevated lesion, 20 cm from the incisor teeth, occupying the entire lumen of the esophagus. The chest computed tomography (CT) scan showed a lesion of 7 cm and superior mediastinal, lower paraesophageal and cardiac enlarged lymph nodes. A posterolateral thoracotomy was performed with total esophagectomy without intraoperative complications. The anatomopathological analysis revealed fusocellular mesenchymal neoplasia of low malignancy potential. The immunohistochemical study showed positivity for S-100 protein and KI67 antibodies and absence of staining for CD117, CD34, ALK protein, SMA and Desmin. Thus, the morphological and immunohistochemical findings pointed to the diagnosis of esophageal Schwannoma.

DISCUSSION

Although rare and indolent, Schwannoma occurs in the peripheral nervous system, being uncommon in the esophagus.

CONCLUSION

The immunohistochemical study is essential for the diagnosis, which is based on the positivity for S-100 protein and absence of staining for CD34 and CD117.

NordiQC Assessments of CD117 Immunoassays

This paper is the number 5 in a series developed through a partnership between ISIMM and NordiQC for the purpose of reporting research assessing the performance characteristics of immunoassays in an external proficiency-testing program.

An Uncommon Presentation of Leiomyoma Cecum as a Subcutaneous Abscess of the Right Flank

Cecal leiomyomas are rare benign tumors of smooth muscle arising from the colonic muscularis mucosa or muscularis propria. They are usually asymptomatic in nature and, if symptomatic, may present as pain in the abdomen, intestinal obstruction, or bleeding. In some cases, leiomyoma can cause free perforation leading to peritonitis. Contrast-enhanced computed tomography (CECT) and colonoscopy were the diagnostic modalities used for evaluation. It is extremely unusual for a benign lesion of the cecum to present as a ruptured subcutaneous abscess. A 40-year-old man presented to the surgical emergency with complaints of right loin swelling and dull aching pain for one week. The patient did not have any significant medical history. Examination revealed a 5×5 cm swelling in the right anterior lumbar region. Blood investigations revealed anemia with leukocytosis. An abdominal CECT revealed a 9×6 cm heterogeneous enhancing mass lesion arising from the cecum with hypodense areas abutting the anterior abdominal wall and tracking into the intermuscular plane. The patient underwent surgical exploration, and a 9×6 cm growth arising from the cecum with a localized abscess tracking into the intermuscular plane in the right anterior abdominal wall and forming a subcutaneous abscess was intraoperatively found. A right hemicolectomy with ileocolic anastomosis was done, with external drainage of the subcutaneous abscess. Histopathological examination of the resected specimen revealed a leiomyoma of the cecum with abscess. To the best of our knowledge, this is the first report of a case of cecal leiomyoma to rupture into the subcutaneous space and present as a flank abscess.

Fractal analysis of contrast-enhanced CT images for preoperative prediction of malignant potential of gastrointestinal stromal tumor

PURPOSE

The purpose of this study is to assess the heterogeneity of tumor enhancement using fractal analysis on contrast-enhanced computed tomography (CE-CT) for predicting malignant potential of gastrointestinal stromal tumor (GIST).

METHODS

We retrospectively identified 64 patients (36 M/28 W; median age: 65) with GISTs who received CE-CT and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) followed by curative surgery. Fractal analysis was applied to CE-CT image, and fractal dimension (FD) was measured. Diagnostic value of FD for malignant potential of GIST was compared with that of FDG-PET using the risk classification and Ki67 index.

RESULTS

14 patients were categorized as the high risk, and 50 patients were as the very low, low or intermediate risk. FD of high-risk group was significantly higher than that of the other-risk group (p < 0.05). The areas under the ROC curves of FD and SUV_max for prediction of high-risk group were 0.82 and 0.93 (accuracy: 84.4% and 98.5%). FD showed a significant positive correlation with Ki67 index (p = 0.01).

CONCLUSION

Diagnostic value of CT fractal analysis for prediction of high-risk GIST is comparable with FDG-PET. In terms of cost and availability, fractal analysis has a potential to be an optimal preoperative biomarker.

Computed tomography findings of small bowel gastrointestinal stromal tumors with different histologic risks of progression

PURPOSE

The purpose of the study was to assess the dynamic contrast-enhanced computed tomography features of small bowel gastrointestinal stromal tumors with different risks of progression.

METHODS

Forty-two patients with SB GISTs underwent dynamic contrast-enhanced CT scan. All CT features of tumors with different risks were analyzed. The correlation of CT attenuation value in different enhancement phases with different risks was analyzed.

RESULTS

In 22 patients, the tumor was in the jejunum, 14 in the ileum, and six in the duodenum. The maximum diameter of the tumors ranged from 1.4 to 21.0 cm (median 8.2 cm). Histologic risk degree was defined according to pathologic findings (three cases were very low risk, 13 cases were low risk, two cases were intermediate risk, and 24 cases were high risk). For all the risk degrees, there were statistical differences in tumor size, heterogeneity, and presence of necrosis (p < 0.05). However, there were no statistical differences in tumor location, presence of calcification, or cystic degeneration (p > 0.05). The CT attenuation value of every risk degree was statistically different in venous phase and delayed phase (p < 0.05).

CONCLUSION

Features on dynamic contrast-enhanced CT can correlate with SB GISTs of different risk categories which may be helpful for preoperative diagnosis and prognosis evaluation.

Cytological Findings of Gastrointestinal Stromal Tumor-Derived Bone Metastasis

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.

Double amplifications of CDK4 and MDM2 in a gastric inflammatory myofibroblastic tumor mimicking cancer with local invasion of the spleen and diaphragm

Inflammatory myofibroblastic tumor (IMT) is currently recognized as an intermediate mesenchymal neoplasm. It can arise anywhere in the body, but it is particularly common in the lungs. Gastric IMT is very rare in adults. In this study, we report a case of a 68-year-old woman with IMT in the gastric cardia, with invasion into the spleen and diaphragm. Because of its location and aggressive clinical features, it was first mistaken for gastric cancer. However, pathology and immunohistochemistry were used to finally confirm the diagnosis of IMT after total resection of the tumor and spleen and partial resection of the diaphragm. In order to provide better understanding of this rare tumor, targeted next-generation sequencing (NGS) and IHC were performed to assess genetic and protein abnormalities of the tumor. Both IHC and NGS were found to be negative for ALK or other gene fusions. However, double amplification of CDK4 and MDM2 were found by NGS, and IHC also found CDK4 and MDM2 to be positive. To the best of our knowledge, this is the first gastric IMT report to show double invasion of the spleen and the diaphragm, and double amplification of CDK4 and MDM2 in IMT are also reported for the first time. This genomic aberration with protein overexpression is the most likely tumorigenic driver of this rare and aggressive tumor.

Gastrointestinal stromal tumors: A clinical and histopathological presentation of 27 cases

OBJECTIVE

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that express type 3 tyrosine kinase receptors and are thought to develop from the neoplastic transformation of the interstitial Cajal cells. The present study was performed to morphologically and immunohistologically evaluate GISTs, to compare their qualities using a GIST risk categorization system, and to identify the diagnostic and prognostic parameters of GISTs.

MATERIAL AND METHODS

A total of 27 patients with GISTs underwent treatment and were followed up at the Gaziosmanpaşa Taksim Training and Research Hospital. Descriptive statistics was used to calculate the mean and median values. Survival analysis was performed by the Kaplan-Meier method. The analyses were performed using the SPSS version 22.0 software.

RESULTS

The mean follow-up time was 3.5 (5 months to 13 years) years. The mean age was 60.4 (29-82) years. The tumors were localized in the stomach (62.9%), extraintestinal areas (14.8%), intestine (7.4%), esophagus (7.4%), and rectum (7.4%). Twenty-four patients were classified according to the Fletcher system. Of these patients, 7 (25.9%) were classified as very low risk, 8 (29.6%) as low risk, 7 (25.9%) as intermediate risk, and 2 (7.4%) as high risk. Twenty-four patients underwent surgery. Of the 3 patients who did not undergo surgery, 1 had metastatic disease at the time of diagnosis, and 2 had mini- or micro-GISTs in the stomach. On endoscopic surveillance, all tumors remained stable. Three out of the 27 patients were lost to follow-up. Two patients developed recurrence, and 1 patient died of GIST.

CONCLUSION

We analyzed the clinical and pathological characteristics of GIST. The most common site of tumor origin was the stomach. The size, mitotic index, and Ki-67 values were to be found high in intermediate- and high-risk groups and metastatic diseases.

Gastrointestinal Stromal Tumors of the Distal Gastrointestinal Tract

Gastrointestinal stromal tumors (GISTs) are rare in occurrence, but comprise the most common mesenchymal tumors of the gastrointestinal tract and affect between 15 and 20 individuals per million per year. Due to recent advancements in molecular classification of these tumors, medical therapy has provided improved outcomes to a historically surgically managed disease. This review article briefly discusses the molecular characteristics, medical and surgical therapies, and future of GIST management.

Endoscopic ultrasound FNA: An illustrated review of spindle cell neoplasms of the upper gastrointestinal tract including a novel case of gastric plexiform fibromyxoma

Plexiform fibromyxoma (PF) is a recently-described and rare mesenchymal neoplasm of the gastric wall. A few small case series reports of this spindle cell entity exist in the surgical pathology literature, but to our knowledge no prior endoscopic ultrasound guided fine needle aspiration cytology examples have been reported. In clinical practice, mural gastrointestinal (GI) lesions are often initially evaluated by endoscopic ultrasound guided (EUS) fine needle aspiration (FNA). In addition, newer EUS fine needle biopsy techniques also allow for reliable retrieval of core tissue samples with intact cellular architecture, making EUS histopathologic analyses possible. We report a combined EUS FNA and core biopsy case of PF and correlate the findings with imaging results. The cytomorphology of PF is described and illustrated, and important entities in the differential diagnosis of upper GI spindle cell lesions (including GI stromal tumor, leiomyoma, schwannoma, carcinoid tumor, desmoid-type fibromatosis, and inflammatory fibroid polyp) are reviewed. Illustrated examples of relevant cytomorphologic, cell block histomorphologic and immunohistochemical characteristics are emphasized.

Invasive inflammatory fibroid polyp of the stomach: a case report and literature review

Background

Inflammatory fibroid polyps (IFPs) are rare mesenchymal lesions that affect the gastrointestinal tract. IFPs are generally considered benign, noninvasive lesions; however, we report a case of an invasive gastric IFP. To the best of our knowledge, this is only the second case report of an invasive gastric IFP.

Case presentation

A 62-year-old woman presented with complaints of epigastric pain and vomiting. Computed tomography showed a 27-mm, hyper-enhancing tumor in the prepyloric antrum. Upper endoscopy also showed a submucosal tumor causing subtotal obstruction of the gastric outlet. Because a gastrointestinal stromal tumor was suspected, distal gastrectomy was performed. Histopathological examination revealed spindle cell proliferation in the submucosal layer. The spindle cells had invaded the muscularis propria layer and extended to the subserosal layer. The tumor was finally diagnosed as an IFP based on immunohistochemical findings. No mutations were identified in the platelet-derived growth factor receptor alpha (PDGFRA) gene via molecular genetic analysis.

Discussion and conclusions

After the discovery that IFPs often harbor PDGFRA mutations, these growths have been considered neoplastic lesions rather than reactive lesions. Based on the present case, IFPs might be considered not only neoplastic but also potentially invasive lesions.

Ulcerated gastric leiomyoma causing massive upper gastrointestinal bleeding: A case report

Leiomyomas are rare, benign submucosal tumors originating from smooth muscle cells. The clinical presentation is usually asymptomatic, with excellent prognosis. We herein report the case of a 68-year-old female with a solitary leiomyoma found during esophagogastroduodenoscopy for hematemesis. Histopathological examination revealed smooth muscle proliferation supported by positive staining for smooth muscle myosin heavy chain and negative staining for CD117 and S-100, consistent with the marker expression pattern of leiomyoma. We report on the clinical presentation of this case, and discuss the origin, epidemiology, treatment and management of leiomyomas.

Clinical Presentation and Treatment of Gastrointestinal Stromal Tumors

Aims and background

Gastrointestinal stromal tumors (GISTs), although rare, are the most common mesenchymal neoplasms affecting the gastrointestinal tract. We present our experience in the treatment of localized and metastatic disease and a review of literature.

Patients and methods

Nine patients were observed from April 2002 to July 2004. Eight tumors were in the gastric area and J was in the small bowel. In 5 cases, complete surgical removal was performed, and none of these patients underwent adjuvant therapy. The remaining 4 cases, with locally advanced or recurrent disease, were treated with imatinib.

Results

The patients with localized disease treated only by surgery did not relapse. In the patients with locally advanced or metastatic disease treated by imatinib, we observed 3 partial responses, and one case was not assessable because he had no measurable disease. In 2 of 3 responders, it was possible to perform a new radical surgery.

Conclusions

Our series is too small to draw any conclusion. According to our review of the literature, surgery remains the standard treatment for non-metastatic GISTs. Imatinib mesylate represents a major breakthrough in the treatment of advanced GISTs and is the first effective systemic therapy for the disease.

Gastrointestinal stromal tumors: 16 years' experience within a university hospital

AIM

the aim was to convey our 16-year experience regarding gastrointestinal stromal tumors within in a high volume university hospital. Factors that may impact on patient survival were evaluated.

MATERIAL AND METHODS

all patients diagnosed with gastrointestinal stromal tumors in our clinic over a 16-year period were retrospectively evaluated. All patients included in the study had their tumors surgically resected. Survival analyses were performed using the Kaplan-Meier method. Survival time comparisons between groups were performed using the log-rank test. The effect of continuous variables on survival times were evaluated via a Cox-regression analysis with a backward conditional method.

RESULTS

one hundred and thirty-five patients (76 males and 59 females) were included into the study and the mean age was 62.8 ± 13.3 years. Overall survival time was 121.3 ± 7.0 months and the 5-year survival rate was 66.6 ± 4.2%. Patients with colorectal tumors had significantly lower survival times than patients with tumors located in the stomach (p = 0.001) and small intestine (p = 0.033). Patients with moderate risk scores had a significantly longer survival compared to patients with high risk scores (p = 0.003) and patients with tumor recurrence had a significantly shorter survival (p < 0.001). There was no significant relationship between survival and factors such as gender and tumor size (p > 0.05). However, age, Ki-67 and the mitotic index were poor prognostic factors and C-kit was considered as a good prognostic factor.

CONCLUSION

some of the findings in this study are consistent with published data. However, our data significantly differs from previous studies such as the common finding of the effect of gender and tumor size on survival.

Molecular characterization and pathogenesis of gastrointestinal stromal tumor

Most gastrointestinal stromal tumors (GISTs) harbor activating mutations in the receptor tyrosine kinase gene KIT or platelet-derived growth factor receptor alpha (PDGFRA), and the resultant activation of downstream signals plays a pivotal role in the development of GISTs. The sites of the tyrosine kinase gene mutations are associated with the biological behavior of GISTs, including risk category, clinical outcome and drug response. Mutations in RAS signaling pathway genes, including KRAS and BRAF, have also been reported in KIT/PDGFRA wild-type GISTs, though they are rare. Neurofibromin 1 (NF1) is a tumor suppressor gene mutated in neurofibromatosis type 1. Patients with NF1 mutations are at high risk of developing GISTs. Recent findings suggest that altered expression or mutation of members of succinate dehydrogenase (SDH) heterotetramer are causally associated with GIST development through induction of aberrant DNA methylation. At present, GISTs with no alterations in KIT, PDGFRA, RAS signaling genes or SDH family genes are referred to as true wild-type GISTs. KIT and PDGFRA mutations are thought as the earliest events in GIST development, and subsequent accumulation of chromosomal aberrations and other molecular alterations are required for malignant progression. In addition, recent studies have shown that epigenetic alterations and noncoding RNAs also play key roles in the pathogenesis of GISTs.

Rare gastrointestinal stromal tumors (GIST): omentum and retroperitoneum

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms that arise in the gastrointestinal tract and rarely elsewhere in the abdomen. GISTs that develop outside the digestive tract are called extra-GISTs (EGISTs). The incidence of EGISTs is reported to be approximately 10% of all GISTs, and the median age is younger than that of conventional GISTs. EGISTs have similar histology and immunohistochemical features as conventional GISTs, with the majority of them in the omentum and mesentery. Most GISTs harbor a kinase-activating mutation in either KIT or PDGFRA. For EGISTs, the incidence of this type of mutation is 40-50%, which is somewhat lower than for conventional GISTs. EGISTs may have a worse prognosis compared with conventional GISTs with high mitotic indices, large size, and distant metastasis including lymph node involvement. In large abdominal tumors, the visceral origin is almost impossible to discern.

Surgical Pathology of Gastrointestinal Stromal Tumors: Practical Implications of Morphologic and Molecular Heterogeneity for Precision Medicine

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.

Resveratrol improves smooth muscle carcinogenesis in the progression of chronic prostatitis via the downregulation of c-kit/SCF by activating Sirt1

PURPOSE

Bladder smooth muscle cell death accompanied by hyperplasia and hypertrophy, as induced by inflammation, is the primary cause for poor bladder function. There are emerging evidences on the role of chronic inflammation as a factor involved in carcinogenesis and progression. We aim to determine the bladder smooth muscle pathological changes and dysfunction in chronic prostatitis (CP), to investigate whether resveratrol can improve the urinary dysfunction and the role of c-kit/SCF pathway, that has been associated with the smooth muscle carcinogenesis.

METHOD

Rat model of CP was established via subcutaneous injections of DPT vaccine and subsequently treated with resveratrol. H&E staining was performed to identify the histopathological changes in prostates and bladders. Western blotting and immunohistochemical staining examined the expression level of C-kit, stem cell factor (SCF), Sirt1, apoptosis associated proteins.

RESULTS

the model group exhibited severe diffuse chronic inflammation, characterized by leukocyte infiltration and papillary frond protrusion into the gland cavities, and a notable increase in prostatic epithelial height. Meanwhile, bladder muscle arranged in disorder with fracture, and cells appeared atypia. The activity of C-kit/SCF was up-regulated, the carcinogenesis associated proteins are dysregulated significantly in CP rats. Resveratrol treatment significantly improved these factors by Sirt1 activation.

CONCLUSIONS

activated c-kit/SCF and bladder muscle carcinogenesis were involved in the pathological processes of CP, which was improved after resveratrol treatment via the downregulation of c-kit/SCF by activating Sirt1.

Complete response to second-line chemotherapy with sunitinib of a gastrointestinal stromal tumor: A case report

Gastrointestinal stromal tumors (GISTs) are a type of sarcoma, and the most common mesenchymal tumor of the gastrointestinal tract. Systemic chemotherapy is recommended for unresectable or metastatic GISTs. Imatinib is an oral multitargeted receptor tyrosine kinase inhibitor that is effective as adjuvant chemotherapy for primary high-risk cases, and as palliative chemotherapy for unresectable or metastatic cases. For imatinib-resistant cases, second-line chemotherapy with sunitinib is recommended due to significantly longer median progression-free survival and higher response rates compared with a placebo. A 54-year-old woman presented with persistent upper abdominal pain and anorexia. An upper gastrointestinal endoscopy and computed tomography revealed a submucosal tumor of the stomach with no apparent metastases. The patient underwent total radical gastrectomy, and was diagnosed histologically with high-risk GIST for recurrence, therefore, the patient received adjuvant chemotherapy with imatinib. However, multiple liver and lymph node metastases were detected, and the patient received sunitinib therapy. After four cycles of sunitinib, the liver and lymph node metastases disappeared, and a complete response (CR) was achieved. To date, there have been no cases of CR in the prospective clinical trials examining the effects of sunitinib, or in case reports worldwide. Therefore, this is a very rare case report of a patient with metastatic GISTs who achieved CR with sunitinib as second-line chemotherapy.

Endosonographic surveillance of 1-3 cm gastric submucosal tumors originating from muscularis propria

AIM

To observe the natural course of 1-3 cm gastric submucosal tumors originating from the muscularis propria (SMTMPs).

METHODS

By reviewing the computerized medical records over a period of 14 years (2000-2013), patients with 1-3 cm gastric SMTMPs who underwent at least two endoscopic ultrasound (EUS) examinations were enrolled. Tumor progression was defined as a ≥ 1.2 times enlargement in tumor diameter observed during EUS surveillance. All patients were divided into stationary and progressive subgroups and further analyzed. We also reviewed the patients in the progressive subgroup again in 2016.

RESULTS

A total of 88 patients were studied, including 25 in the progressive subgroup. The mean time of EUS surveillance was 24.6 mo in the stationary subgroup and 30.7 mo in the progressive subgroup. Risk factors for tumor progression included larger tumor size and irregular border. Initial tumor size > 14.0 mm may be considered a cut-off size for predicting tumor progression. Seventeen patients underwent surgery, of whom 13 had gastrointestinal stromal tumors (GISTs) and 4 had leiomyomas. Tumor progression was found only in patients with GISTs. All of the tumors exhibited benign behaviors without metastasis until 2016.

CONCLUSION

Most 1-3 cm gastric SMTMPs (71.6%) are indolent. Tumor progression was found only in GISTs, and it is a good predictor for differentiating GISTs from leiomyomas. Predictors of tumor progression include larger tumor size (> 14.0 mm) and irregular border.

Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors had the reputation for poor outcomes because of their lack of response to nonsurgical interventions. The discovery of gain-of-function mutations involving receptor tyrosine kinase growth factor receptors altered the biological understanding and management. Beginning in 2000, management of these tumors has changed dramatically because of the availability of tyrosine kinase inhibitors. The role of surgery continues to be refined. This article reviews how surgery and systemic therapy are being used, incorporating definitions of risk. Decisions on how to treat a patient is based on the risk of progression, pathologic characteristics, and tumor location.

Endoscopic ultrasonographic characteristics of gastric schwannoma distinguished from gastrointestinal stromal tumor

BACKGROUND/AIMS

Gastric schwannoma (GS), a rare neurogenic mesenchymal tumor, is usually benign, slow-growing, and asymptomatic. However, GS is often misdiagnosed as gastrointestinal stromal tumors (GIST) on endoscopic and radiological examinations. The purpose of this study was to evaluate EUS characteristics of GS distinguished from GIST.

METHODS

A total of 119 gastric subepithelial lesions, including 31 GSs and 88 GISTs, who were histologically identified and underwent EUS, were enrolled in this study. We evaluated the EUS characteristics, including location, size, gross morphology, mucosal lesion, layer of origin, border, echogenic pattern, marginal halo, and presence of an internal echoic lesion by retrospective review of the medical records.

RESULTS

GS patients comprised nine males and 22 females, indicating female predominance. In the gross morphology according to Yamada's classification, type I was predominant in GS and type III was predominant in GIST. In location, GSs were predominantly located in the gastric body and GISTs were predominantly located in the cardia or fundus. The frequency of 4th layer origin and isoechogenicity as compared to the echogenicity of proper muscle layer was significantly more common in GS than GIST. Although not statistically significant, marginal halo was more frequent in GS than GIST. The presence of an internal echoic lesion was significantly more common in GIST than GS.

CONCLUSIONS

The EUS characteristics, including tumor location, gross morphology, layer of origin, echogenicity in comparison with the normal muscle layer, and presence of an internal echoic lesion may be useful in distinguishing between GS and GIST.

C-Kit, CD34 & α-SMA Immunohistochemical Features in Classic Kaposi Sarcoma and Kaposiform Hemangioendothelioma

Purpose & Methods:

The aim of this work was to study the clinicopathological features of Kaposi sarcoma (KS) & kaposiform hemangioendothelioma (KHE) and analyze their immunohistochemical expression of c-Kit, CD34, α-SMA. The study was performed on cutaneous 10 classic KS & 8 KHE.

Results:

KHE shows several dilated lymphatic channels, focal capillary formation, lack of nuclear atypia and mitosis within tumor cells. These features help to exclude Kaposi sarcoma in spite of the kaposiform pattern of tumor cells. C-Kit was expressed by tumor cells in all KHE cases and in 60% only of KS. All elements within both tumor groups expressed CD34 antibody. α-SMA was expressed by tumor cells in 70% of KS cases and none of KHE.

Conclusion:

C-Kit and CD34 seem to be reliable at labeling KS and KHE as they can help in diagnosis of these tumors in routinely processed tissue but they don’t differentiate between them. If α-SMA also labeled the tumor, then KHE diagnosis can be ruled out. KS & KHE exemplify stem cell tumors that could give smooth muscle cell–like phenotype in KS. Anti C-kit therapy should be tested in KS & KHE to prevent recurrence.

Laparoscopic Transgastric Resection of a Gastric Submucosal Tumor near Esophagogastric Junction with Concomitant Sleeve Gastrectomy: a Video Case Report

BACKGROUND

Over the past two decades, there has been a significant rise in bariatric surgery. As a consequence, the prevalence of obese patients with a combined gastric pathology such as a submucosal tumor (SMT) requiring excision at the same time as bariatric surgery is higher but the management remains controversial. We report the safety and effectiveness of a simultaneous laparoscopic transgastric resection of a large gastric SMT near the esophagogastric junction (EGJ) with sleeve gastrectomy (SG).

METHODS

We present a video report of a 52-year-old male (BMI = 49 kg/m²) referred for bariatric surgery, who was found to have a large SMT 2 cm from the EGJ on the lesser curvature on previous gastroscopy.

RESULTS

Using five ports placed for laparoscopic SG, the gastric SMT was localized through an anterior gastrotomy and fully excised using a linear stapler and the gastrotomy site was closed. SG was then performed over a 54Fr bougie, including the gastrotomy suture closure.

CONCLUSIONS

Several factors play important roles in deciding the best surgical approach for patients who are candidates for bariatric surgery and have concomitant gastric SMTs. This video report describes a safe and effective technique of simultaneous transgastric resection of a lesser curvature gastric SMT near the EGJ in a patient undergoing SG.

Cytologic and Immunohistochemical Evaluation of Low-Grade Spindle Cell Lesions of the Gastrointestinal Tract

Spindle cell lesions of the gastrointestinal tract are relatively uncommon compared with the frequency of their epithelial counterparts. Although gastrointestinal stromal tumors and leiomyomas are the most commonly encountered spindle cell lesions in the stomach and esophagus, respectively, there are other less common diagnostic entities that should be considered for accurate diagnoses as well as appropriate patient treatment and clinical follow-up. Given the morphologic overlap of low-grade spindle cell lesions on cytologic preparations, ancillary studies play a key role in differentiating these lesions from one another.

Molecular subtypes of gastrointestinal stromal tumors and their prognostic and therapeutic implications

Gastrointestinal stromal tumors (GISTs) are composed of various molecular subtypes, with differing prognostic and predictive relevance. Previously, tumors lacking mutations in the KIT and PDGFRA genes have been designated as 'wild-type' GISTs; however, they represent a heterogeneous group currently undergoing further subclassification. Primary and secondary resistance to imatinib poses a significant clinical challenge, therefore ongoing research is trying to evaluate mechanisms to overcome resistance. Thorough understanding of the prognostic and predictive relevance of different genetic subtypes of GIST can guide clinical decision-making both in the adjuvant and the metastatic setting. Further work is required to identify tailored therapies for specific subgroups of GISTs wild-type for KIT and PDGFRA mutations and to identify predictive factors of resistance to currently approved systemic therapies.

[Intestinal intussusception secondary to myofibroblastic tumor in an elderly patient. Case report]

BACKGROUND

Intussusception is defined as a segment of the gastrointestinal tract and mesentery within the lumen of an adjacent segment. It is a rare condition in adults that can occur anywhere in the gastrointestinal tract from the stomach to the rectum. Only 5% of all intussusceptions are presented in adults, and in 1-5% of all cases of intestinal obstruction. Inflammatory myofibroblastic tumour is rare, and is usually found in the lung, and rarely detected in some intestinal portions. It causes a variety of non-specific symptoms, with those that present as an intussusception being uncommon.

CLINICAL CASE

A female of 69 years with partial bowel obstruction secondary to intestinal intussusception due to an inflammatory myofibroblastic tumour, a rarely diagnosed condition and never published before.

DISCUSSION

Inflammatory myofibroblastic tumours are rare, and in this case with an atypical presentation that was surgically resolved satisfactorily. These entities are difficult to diagnose, with histopathology giving the definitive diagnosis. A literature review was performed to gather recent information about their diagnosis and treatment.

CONCLUSIONS

Inflammatory myofibroblastic tumours require a high level of suspicion, as diagnosis prior to surgery is difficult. Surgery is considered the treatment of choice, requiring leaving free surgical edges to prevent recurrences.

Quadruple-Negative GIST Is a Sentinel for Unrecognized Neurofibromatosis Type 1 Syndrome

PURPOSE

The majority of gastrointestinal stromal tumors (GIST) are driven by KIT, PDGFRA, or, less commonly, BRAF mutations, and SDH gene inactivation is involved in a limited fraction of gastric lesions. However, about 10% of GISTs are devoid of any of such alterations and are poorly responsive to standard treatments. This study aims to shed light on the molecular drivers of quadruple-negative GISTs.

EXPERIMENTAL DESIGN

Twenty-two sporadic quadruple-negative GISTs with no prior association with Neurofibromatosis Type 1 syndrome were molecularly profiled for a panel of genes belonging to tyrosine kinase pathways or previously implicated in GISTs. For comparison purposes, 24 GISTs carrying KIT, PDGFRA, or SDH gene mutations were also analyzed. Molecular findings were correlated to clinicopathologic features.

RESULTS

Most quadruple-negative GISTs featured intestinal localization, with a female predilection. About 60% (13/22) of quadruple-negative tumors carried NF1 pathogenic mutations, often associated with biallelic inactivation. The analysis of normal tissues, available in 11 cases, indicated the constitutional nature of the NF1 mutation in 7 of 11 cases, unveiling an unrecognized Neurofibromatosis Type 1 syndromic condition. Multifocality and a multinodular pattern of growth were common findings in NF1-mutated quadruple-negative GISTs.

CONCLUSIONS

NF1 gene mutations are frequent in quadruple-negative GISTs and are often constitutional, indicating that a significant fraction of patients with apparently sporadic quadruple-negative GISTs are affected by unrecognized Neurofibromatosis Type 1 syndrome. Hence, a diagnosis of quadruple-negative GIST, especially if multifocal or with a multinodular growth pattern and a nongastric location, should alert the clinician to a possible Neurofibromatosis Type 1 syndromic condition. Clin Cancer Res; 23(1); 273-82. ©2016 AACR.

Differentiating gastrointestinal stromal tumors from gastric adenocarcinomas and normal mucosae using confocal Raman microspectroscopy

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract, and gastric adenocarcinomas are a common cancer worldwide. To differentiate GISTs from adenocarcinomas is important because the surgical processes for both are different; the former excises the tumor with negative margins, while the latter requires radical gastrectomy with lymph node dissection. Endoscopy with biopsy is used to distinguish GISTs from adenocarcinomas; however, it may cause tumor bleeding in GISTs. We reported here the confocal Raman microspectroscopy as an effective tool to differentiate GISTs, adenocarcinomas, and normal mucosae. Of 119 patients enrolled in this study, 102 patients underwent gastrectomy (40 GISTs and 62 adenocarcinomas), and 17 patients with benign lesions were obtained as normal mucosae. Raman signals were integrated for 100 s for each spot on the specimen, and 5 to 10 spots, depending on the sample size, were chosen for each specimen. There were significant differences among those tissues as evidenced by different Raman signal responding to phospholipids and protein structures. The spectral data were further processed and analyzed by using principal component analysis. A two-dimensional plot demonstrated that GISTs, adenocarcinomas, and normal gastric mucosae could be effectively differentiated from each other.

Inflammatory myofibroblastic tumor: A rare cause of invagination in adults

Inflammatory myofibroblastic tumor (IMT) is a distinct pseudosarcomatous lesion arising in the soft tissues and interior organs of children and young adults. It is rarely seen in adults. It was first described in lungs. IMT can occur in any location in the body. However, it is seen most commonly in lungs, intestinal mesentery and liver. Non-mesenteric alimentary tract IMT's are quite rare. The presented case is an ileal IMT that caused small bowel invagination. A 38 year-old male patient presented to the emergency department with the complaint of diffuse abdominal pain, distension and no passage of gas or stools for two days. An abdominal examination revealed distension and tenderness in the abdomen with no guarding or rebound tenderness. Computerized tomography (CT) of the abdomen was ordered. CT revealed an image compatible with invagination of the right lower quadrant of the abdomen and a mass inside the lumen measuring 4x3x3cm. The mass causing invagination was detected during the surgical operation. A segmentary small bowel resection and ileoileal anastomosis was performed. The patient was discharged uneventfully on the postoperative sixth day. The diagnosis of IMT was confirmed histologically and immunochemically.

Gastric schwannoma misdiagnosed as GIST: A case report with immunohistochemical and molecular study

Schwannomas are tumors derived from Schwann cells. Generally, they are benign and their typical site of origin is the subcutaneous tissue of the distal extremities or of the head and neck region. Gastrointestinal localization of schwannomas is extremely rare, and the stomach is the prevalent site. The present study describes the case of a gastric schwannoma in a 61-year-old male who underwent subtotal gastrectomy following a clinical diagnosis of a gastrointestinal stromal tumor (GIST). A histological, immunohistochemical and molecular study was performed to exclude the misdiagnosis of GIST. The histomorphological features of the lesion and absence of c-Kit and PDGFRA mutations indicated the diagnosis of gastric schwannoma.

Plexiform fibromyxoma with cotyledon-like serosal growth: A case report of a rare gastric tumor and review of the literature

Plexiform fibromyxoma is a rare, benign mesenchymal neoplasm that predilects the gastric antrum and has potential for misdiagnosis as a gastrointestinal stromal tumor (GIST). The histology of the tumor is characterized by interwoven fascicular growth of cytologically bland spindled cells within a variably myxoid stroma. The current study reports the clinicopathological and immunohistochemical findings of a plexiform fibromyxoma resected from a 28-year-old Vietnamese female. The patient presented with acute, severe abdominal pain and worsening anemia. The initial fine-needle aspiration and needle core biopsy of the gastric antral mass led to an initial diagnosis of GIST. The subsequent distal partial gastrectomy revealed a 5.5-cm transmural antral mass that ulcerated the overlying mucosa and grew as variably elongated, myxoedematous, polypoid (cotyledon-like) excrescences from the serosal surface. Microscopically, the tumor demonstrated plexiform and multinodular growth of cytologically bland spindled cells proliferating in an abundant myxocollagenous stroma with a prominent capillary network. Tumor cells immunohistochemically expressed smooth muscle actin and CD10, but did not express CD117, Discovered on GIST-1 or nuclear β-catenin. Follow-up evaluation 23 months post surgery revealed no evidence of residual tumor. A review the cases of this rare entity reported in the English language literature is also provided.

Novel receptor tyrosine kinase targeted combination therapies for imatinib-resistant gastrointestinal stromal tumors (GIST)

Background: c-Kit/α-PDGFR targeted therapies are effective for gastrointestinal stromal tumors (GIST), but, >50% develop drug resistance.

Methods: RTK expression (c-Kit, c-Met, AXL, HER-1, HER-2, IGF-1R) in pre-/post-imatinib (IM) GIST patient samples (n=16) and 4 GIST cell lines were examined for RTK inhibitor activity. GIST-882 cells were cultured in IM every other day, cells collected (1 week to 6 months) and analyzed by qRT-PCR and Western blotting.

Results: Immunohistochemistry pre-/post-IM demonstrated continued expression of c-Kit and HER1, while a subset expressed IGF-1R, c-Met and AXL. In GIST cells (GIST-882, GIST430/654, GIST48) c-Kit, HER1 and c-Met are co-expressed. Acute IM over-express c-Kit while chronic IM, lose c-Kit and HER-1 in GIST882 cells. GIST882 and GIST430/654 cells have an IC₅₀ 0.077 and 0.59 μM to IM respectively. GIST48 have an IC₅₀ 0.66 μM to IM, 0.91 μM to amuvatinib [AMU] and 0.67 μM to erlotinib (Erl). Synergistic combinations: GIST882, AMU + Erl (CI 0.20); IM + AMU (CI 0.50), GIST430/654, IM + afatinib (CI 0.39); IM + AMU (CI 0.42), GIST48, IM + afatinib (CI 0.03); IM + AMU (CI 0.04); AMU + afatinib (CI 0.36); IM + Erl (CI 0.63).

Conclusion: Targeting c-Kit plus HER1 or AXL/c-Met abrogates IM resistance in GIST.

C-kit Mutations in Endometrial Cancer: Correlation with Tumor Histologic Type

OBJECTIVE

Endometrial cancer is the fourth most common cancer among women in developed countries. Affected patients may benefit from systemic chemotherapy, alone or in combination with targeted therapies if the disease is clinically diagnosed prior to expansion and metastasis to other organs.The aim of this study was to evaluate the prognostic role of c-kit mutations and comparision with tumor type and grade in human uterine endometrial carcinomas.

MATERIALS AND METHODS

Seventy five patients with endometrial carcinoma and seventy five normal controls were studied for possible mutations in exon 17 of the c-kit gene using single strand conformational polymorphisms and sequencing.

RESULTS

c-kit mutation in exon 17 appeared to be significantly different between endometrial carcinoma and normal endometrium. The pattern and frequency of the mutations was also shown to be different between tumors from different stages.

Clinicopathologic analysis of gastrointestinal stromal tumors in duodenum and small intestine

BACKGROUND

The prognosis about duodenal GISTs is debatable. The purpose of this study is to compare the characteristics and the prognostic factors in patients with gastrointestinal stromal tumor (GIST) located in the duodenum with those located in the small intestine.

METHODS

One hundred-one patients with GIST located in the duodenum (n = 40), or small intestine (n = 61) underwent resection between 1996 and 2010. We analyzed clinicopathologic features, surgical outcomes, and prognostic factors.

RESULTS

Five-year survival rate in patients with GIST located in the duodenum and small intestine were 66.6 and 80.8%, respectively (p = 0.018). After survival analysis, high mitotic count and tumor rupture were identified as independent adverse prognostic factors. Advanced T stage and absence of adjuvant imatinib treatment were adverse prognostic factors with marginal statistical significance. The rate of progressive disease was significantly higher in patients with duodenal GISTs (36.8%) than in those with small intestinal GIST (29.6%) (p = 0.024).

CONCLUSIONS

The clinicopathologic findings of duodenal GIST differ from those of small intestinal GIST. Patients with duodenal GIST have a worse prognosis than those with small intestinal GIST. Aggressive treatment including surgical resection should be considered for duodenal GIST, even if the risk is relatively low.

Duodenal gastrointestinal stromal tumor: From clinicopathological features to surgical outcomes

Duodenal gastrointestinal tumors represent an extremely rare subset of stromal tumors arising from interstitial cells of Cajal. In the last 30 years the comprehension of the pathophysiology and natural history of this previously misunderstood clinical entity, in association with developments in endoscopy, imaging technology, and immunohistochemistry has resulted in novel diagnostic and treatment approaches. This is a comprehensive review of the current data of the literature on the various aspects of the diagnosis and treatment of these tumors. The duodenum is the less commonly involved site for these tumors in the digestive tract. Endoscopy and computed tomography can usually establish the diagnosis, confirmed by immunohistochemical staining and occasionally molecular genetic analysis. Endoscopic ultrasound with fine needle aspiration has been recently found to be the gold diagnostic standard with high sensitivity and specificity rates, diagnosing GIST in up to 80% of patients. Due to the complex anatomy of the pancreatico-duodenal region optimal therapeutic strategy of duodenal GISTs are challenging. Nevertheless surgical resection with microscopically clear resection margins seems to be the only potentially curative treatment for non-metastatic primary GISTs of the duodenum. Imatinib mesylate plays a key role in the management of GISTs both as neoadjuvant therapy and in patients with recurrent and metastatic disease. Meanwhile, the advances in the comprehension of the pathophysiology and natural history of this previously misunderstood clinical entity as well as the treatment of these tumors may render feasible, in the near future, the advent of newer and more effective treatment options.

Gastrointestinal Stromal Tumors (GIST): A Prospective Analysis and an Update on Biomarkers and Current Treatment Concepts

Gastrointestinal stromal tumors (GIST) are the most common sarcomas of the gastrointestinal tract, with transformation typically driven by activating mutations of cKIT and less commonly platelet-derived growth factor receptor alpha (PDGFRA). Successful targeting of tyrosine-protein kinase Kit with imatinib, a tyrosine kinase inhibitor, has had a major impact in the survival of patients with GIST in both the adjuvant and metastatic setting. A recent modification of treatment guidelines for patients with localized, high-risk GIST extended the adjuvant treatment duration from 1 year to 3 years. In this paper, we review the clinical data of patients with GIST treated in the Oncology Outpatient Unit of "Attikon" University Hospital and aim to assess which patients are eligible for prolongation of adjuvant imatinib therapy as currently suggested by treatment recommendations.

Clinical significance of expression of KCTD-12 in gastrointestinal stromal tumors of the stomach

AIM: To investigate the expression of potassium channel tetramerization domain-containing 12 (KCTD-12) protein in gastrointestinal stromal tumors (GISTs) of the stomach and its clinical significance.

METHODS: The expression of KCTD-12 was immunohistochemically examined in 39 gastric GIST tissues, and its correlations with the clinicopathological parameters, National Institutes of Health (NIH) risk classification and Ki-67 labeling index were analyzed. Univariate and Cox multivariate analyses were used to evaluate the factors associated with 3-year recurrence-free survival (RFS) rate of patients with gastric GISTs.

RESULTS: Positive KCTD-12 expression was detected in 29 (74.4%) of the 39 gastric GIST tissues. The absence of KCTD-12 expression was associated with large tumor size, high mitotic count and NIH high-risk classification (P < 0.05). GISTs recurred after surgery in 10 of the 39 cases during the follow-up, and the 3-year RFS rate was 74.4%. Univariate analysis showed that tumor size, NIH risk classification, KCTD-12 expression and Ki-67 labeling index had an impact on the 3-year RFS rate of patients with GISTs of the stomach. On multivariate analysis, KCTD-12 [relative risk (RR) = 0.014; 95%CI: 0.001-0.320, P = 0.007] was shown to be a highly correlated predictor. The 3-year RFS rate of patients without KCTD-12 expression was only 30% compared with 89.7% in those with KCTD-12 expression (P = 0.001). The 3-year RFS rate of patients with KCTD-12 expression and a Ki-67 labeling index of 5% or less was 95.7%. The 3-year RFS rate of patients without KCTD-12 expression and a Ki-67 labeling index more than 5% was only 20%.

CONCLUSION: KCTD-12 is a useful and reliable biomarker for the prognosis of GISTs of the stomach, especially when combined with Ki-67 labeling index.

Is wide resection obsolete for desmoid tumors in children and adolescents? Evaluation of histological margins, immunohistochemical markers, and review of literature

Desmoid fibromatosis is a benign fibroblastic neoplasm with high recurrence rates predominantly observed in pediatric and adolescent patients. The use of wide resection margins has been discussed controversially in literature. In addition, data on non-surgical treatment is limited as phase III studies are still missing. Nineteen patients under the age of 18 years were identified. Tumor location, surgical treatment for primary or recurrent tumors, resection margins, medical neo-/adjuvant treatment, time to recurrence as well as immunohistochemical markers (estrogen receptor, ER α and β, progesterone and androgen receptors, somatostatin, Ki-67, c-kit, platelet-derived growth factor receptors, PDGFRs, α and β, β-catenin) were evaluated. The mean age at diagnosis was 6.6 years, with a mean follow-up of 114 months. Recurrences were detected in four out of nineteen patients. Surprisingly, the recurrence rate was not influenced by type of resection used (R0, R1/2). All samples were tested negative for ER α, somatostatin, and progesterone receptor. In contrast, a majority of tumors showed positive results for PDGFR α and β and β-catenin. No correlation between positive immunohistochemical markers and tumor recurrences was detectable. In conclusion, recurrence rates are not depending on resection type and immunohistochemical markers seem to behave differently in children and adolescents in contrast to adult patients.

Epigenetic alterations in a gastric leiomyoma

Leiomyomas constitute 2.5% of all resected neoplasms of the stomach. They are usually asymptomatic, but may present mucosal ulceration. Aberrant DNA methylation is a well-defined epigenetic change in human neoplasms; however, gene-acquired methylation may not necessarily be related with a malignant phenotype. In this report we analyzed in a gastric leiomyoma, the methylation status of 84 CpGI in tumor suppressor and DNA repair genes. We analyzed the tumor center (TC) and tumor periphery (TP) separately. We found aberrant methylation in 2/84 CpGI in the TC portion, that is, MLH1 and MSH3, and 5/84 CpGI in the TP, that is, MLH1, MSH3, APC, MSH6, and MGMT. The gene with the highest methylation percentage in the TC and TP was MLH1. Given that MLH1 methylation has been associated with microsatellite instability, we analyzed the status of the microsatellite Bat-26. We found that neither the TC nor the TP presented instability. The methylation of MLH1, MGMT, and APC has been described in GISTs, but to the best of our knowledge this is the first time that the methylation of these genes has been associated with gastric leiomyoma. Further research should be conducted to identify reliable molecular markers that could differentiate between GISTs and gastric leiomyomas.

Transsacral excision with pre-operative imatinib mesylate treatment and approach for gastrointestinal stromal tumors in the rectum: A report of two cases

Gastrointestinal stromal tumors (GISTs) are rare in the rectum. Radical surgery, such as an abdominoperineal resection, is necessary for large rectal GISTs, which can result in the loss of function of involved organs. Imatinib mesylate can be used as perioperative therapy and may reduce tumor size, and it is now approved for use in the adjuvant therapy of locally resected anorectal GISTs. The present study describes two cases of large rectal GISTs, for which abdominoperineal resections were initially planned. The two patients received pre-operative imatinib mesylate treatment, and the therapeutic response was assessed by magnetic resonance imaging. Finally, transsacral local resection was successfully performed for these two GISTs. A macroscopically complete resection was achieved, and microscopically, the resection margin was negative. One patient experienced the complication of rectal leakage, which was successfully managed by drainage. No recurrence occurred in the two patients after more than two years. Pre-operative imatinib mesylate therapy with subsequent transsacral local resection for selected rectal GISTs is a feasible treatment modality and can prevent extended surgery.