Role of endoscopic ultrasound and endoscopic resection for the treatment of gastric schwannoma

Gastric schwannoma with post-surgical gastroparesis: a case report and literature review

Gastric schwannoma is a relatively rare submucosal mesenchymal tumor with low probability of metastasis and arises from Schwann cells of the gastrointestinal nervous plexus. Surgical therapy is the main treatment of gastric schwannoma with symptoms or malignant tendency. Gastroparesis is a potential complication following gastrointestinal surgery, which is a clinical syndrome caused by gastric emptying disorder and characterized by nausea, vomiting, and bloating, resulting in insufficient nutrient intake. Generally, post-surgical etiology is the main potential etiology of gastroparesis, while the most common underlying etiology is diabetes mellitus. So far, reports of gastroparesis arising from resection of gastric schwannoma are rare. We present an 80-year-old woman who was diagnosed with gastrointestinal stromal tumor (GIST) primarily and has undergone laparoscopic wedge-shaped gastrectomy. The pathological and immunohistochemical examination ultimately established the diagnosis of gastric schwannoma. The patient experienced belching, nausea, vomiting, and bloating 1 week after the surgery and confirmed as gastroparesis through gastrointestinal series and gastroscopic examination. A series of treatments were performed, including correcting fluid-electrolyte disorders and vitamin deficiencies, and nutritional support and pharmacological treatments. The patient ultimately recovered well, and the relevant literatures were reviewed to identify and handle similar cases hereafter.

Preoperative differentiation of gastric schwannomas and gastrointestinal stromal tumors based on computed tomography: a retrospective multicenter observational study

Introduction

Gastric schwannoma is a rare benign tumor accounting for only 1-2% of alimentary tract mesenchymal tumors. Owing to their low incidence rate, most cases are misdiagnosed as gastrointestinal stromal tumors (GISTs), especially tumors with a diameter of less than 5 cm. Therefore, this study aimed to develop and validate a diagnostic nomogram based on computed tomography (CT) imaging features for the preoperative prediction of gastric schwannomas and GISTs (diameters = 2-5 cm).

Methods

Gastric schwannomas in 47 patients and GISTs in 230 patients were confirmed by surgical pathology. Thirty-four patients with gastric schwannomas and 167 with GISTs admitted between June 2009 and August 2022 at Hospital 1 were retrospectively analyzed as the test and training sets, respectively. Seventy-six patients (13 with gastric schwannomas and 63 with GISTs) were included in the external validation set (June 2017 to September 2022 at Hospital 2). The independent factors for differentiating gastric schwannomas from GISTs were obtained by multivariate logistic regression analysis, and a corresponding nomogram model was established. The accuracy of the nomogram was evaluated using receiver operating characteristic and calibration curves.

Results

Logistic regression analysis showed that the growth pattern (odds ratio [OR] 3.626; 95% confidence interval [CI] 1.105-11.900), absence of necrosis (OR 4.752; 95% CI 1.464-15.424), presence of tumor-associated lymph nodes (OR 23.978; 95% CI 6.499-88.466), the difference between CT values during the portal and arterial phases (OR 1.117; 95% CI 1.042-1.198), and the difference between CT values during the delayed and portal phases (OR 1.159; 95% CI 1.080-1.245) were independent factors in differentiating gastric schwannoma from GIST. The resulting individualized prediction nomogram showed good discrimination in the training (area under the curve [AUC], 0.937; 95% CI, 0.900-0.973) and validation (AUC, 0.921; 95% CI, 0.830-1.000) datasets. The calibration curve showed that the probability of gastric schwannomas predicted using the nomogram agreed well with the actual value.

Conclusion

The proposed nomogram model based on CT imaging features can be used to differentiate gastric schwannoma from GIST before surgery.

Gastric schwannoma: The gastrointestinal tumor simulator - case report and review of the literature

INTRODUCTION AND IMPORTANCE

Gastric schwannoma is a rare and benign tumor originating from the peripheral nerves of the stomach. Despite its benign nature, this tumor typically remains asymptomatic for an extended period, and its radiological and endoscopic presentation poses challenges in distinguishing it from other gastric mesenchymal tumors.

CASE PRESENTATION

Here, we present a rare case of a patient experiencing gastric pain and melena secondary to a gastric mass. The initial preoperative diagnosis indicated a gastrointestinal stromal tumor, but subsequent pathological and immunohistochemical staining of the surgical specimen confirmed the presence of gastric schwannoma.

DISCUSSION

To gain insights into this uncommon condition, we conducted an electronic search on PubMed using the keywords "gastric schwannoma" and "gastric neurinoma." Our focus centered on case series containing more than five cases of gastric localization, resulting in the analysis of 14 case series involving a total of 321 patients. Our review aims to comprehensively discuss the clinical, radiological, and therapeutic aspects associated with this rare disease.

CONCLUSION

In the absence of a definitive preoperative diagnosis, the surgical approach is considered the primary treatment for resectable gastric schwannoma, given its excellent long-term outcomes. However, further studies are imperative to better define the role of endoscopic resection in managing this condition.

Gastric schwannoma: A retrospective analysis of clinical characteristics, treatments, and outcomes

BACKGROUND

This study aimed to investigate the clinical characteristics, treatment options, and prognosis of patients with gastric schwannoma (GS).

METHODS

Patients who were pathologically diagnosed with GS between April 2011 and October 2022 were enrolled. The data of clinical characteristics, pathological features, treatment options, and clinical outcomes were collected and compared between GS patients who underwent endoscopic resection (ER) and surgical resection (SR).

RESULTS

Of the 32 cases, 23 underwent SR and nine underwent ER. The median tumor size was significantly smaller in ER group than in SR group (12.0 vs. 40.0 mm, P < 0.001), while patients in SR group were older than those in ER group (54.5 ± 10.6 vs. 45.3 ± 10.9 years, P = 0.036). Moreover, tumors in ER group were more likely to exhibit an intraluminal pattern (100% vs. 26.1%, P < 0.001). Patients in ER group had significantly lower hospitalization cost (25859.2 ± 8623.9 vs. 44953.0 ± 13083.8 RMB, P = 0.011) than those in SR group. No differences were found between the two groups in terms of R0 resection rate, operative time, estimated blood loss, adverse events, and recurrence rate. All patients were followed up for 4-96 months (mean: 35 months; median: 23 months), during which no evidence of recurrence or metastasis was observed.

CONCLUSIONS

Both ER and SR are safe and effective treatment modalities for the management of GS, with ER being associated with lower medical costs compared to SR. The majority of GS are benign and do not recur, with little possibility of malignant transformation.

Challenging Diagnosis: Unmasking the Enigma of Imaging Findings with Lung Schwannomas

Schwannomas are benign slow-growing tumors arising from the embryonic neural crest cells of the nerve sheaths of peripheral and cranial nerves, and they are a rare type of soft tissue mass that is usually always solitary. Generally, it grows in the head, neck, and flexor portions of the limbs, where many nerves are located. Schwannomas of the lung are extremely rare. Fewer than ten cases of schwannomas in this organ region have been reported in the existing literature. In this case report, a 40-year-old male non-smoker was hospitalized with occasional chest pain. His chest computed tomographic scan revealed a 3.8 cm space occupying lesion in the upper lobe of the right lung. This lesion has clear boundaries and uneven internal density. And it was concluded as a benign lesion possibility, it is preferred to be considered as a haematoma. This space occupying lesion was eventually confirmed as a schwannoma by needle biopsy tissues. Due to the presence in rare locations, such as the lung, the clinical presentation of this space occupying lesion is non-specific, making diagnosis difficult. The data presented in this case report can help clinicians to obtain information on the identification of this disease, which highlighted lung schwannoma as a differential diagnosis for patients with intermittent pain. It can also alert clinicians and radiologists to observe every detail of the radiology imaging findings.

PET Scanning May Not Distinguish Benign Schwannoma from Metastasis in a Patient with Lung Adenocarcinoma

A 69-year-old man was diagnosed with lung adenocarcinoma with metastasis because two masses in the right intercostal space and right back muscle showed high accumulation on positron emission tomography (PET). The 6-month treatment with osimertinib significantly reduced his lung lesion, but no changes were observed in the metastatic lesions. Needle biopsy revealed that the lesion in the right back muscle was a schwannoma. Surgical resection revealed that the right intercostal lesion was also a schwannoma; subsequently, a right upper lobectomy was performed. The patient was finally diagnosed with lung adenocarcinoma without metastasis. High accumulations of lesions observed on PET may indicate schwannomas.

LEARNING POINTS

Benign schwannomas could show high accumulations on positron emission tomography.Accurate diagnosis of schwannoma using only images is quite challenging.Histological examinations should be considered when asymptomatic lesions are suspected to be metastases.

Clinicopathological characteristics of gastrointestinal schwannomas: A retrospective analysis of 78 cases

INTRODUCTION

Schwannomas are tumors arising from Schwan cells of the neural sheath, which rarely occur in the gastrointestinal tract. The aim of the present study was to analyze the clinicopathological features and treatment outcomes of gastrointestinal schwannomas (GISs).

METHODS

Patients who were diagnosed with GISs in our hospital from January 2010 to December 2021 were selected. Data about demographic characteristics, clinical symptoms, treatment methods and outcomes, pathological results, and follow-up results were retrospectively collected and analyzed.

RESULTS

A total of 78 patients with 79 GISs were included, the female-to-male ratio was 55:23, and the average age was 52.12 ± 12.26 years. One-third (26/78) of the patients were asymptomatic. A total of 79 GISs were removed, and the average size was 3.63 ± 2.03 cm (range, 0.3-10 cm). As for tumor location, 54 GISs were located in the stomach, 14 in the esophagus, 2 in the duodenum, 6 in the colorectum (4 in the colon and 2 in the rectum), and the other 3 in the small intestine. A total of 23 and 55 patients underwent endoscopic and surgical resections, respectively. Compared with surgical resection, endoscopic resection is associated with a smaller diameter, lower cost, and shorter hospital stay. Pathological results revealed that S100 was positive in all the GISs. No recurrence was noticed during a median follow-up of 45 months (range, 6-148 months).

CONCLUSION

GISs are rare gastrointestinal tumors with favorable prognoses, which are most commonly seen in the stomach and diagnosed by pathological findings with immunohistochemical staining. Surgical resection remains the standard method for removing GISs, while endoscopic resection may serve as an alternative method for selected patients with GISs and may be attempted in GISs with a diameter of <3 cm and no signs of malignancy.

Laparoscopic partial cystectomy through extraperitoneal space for primary bladder schwannoma

BACKGROUND

Schwannomas can occur in the body where nerve sheaths are present. Genitourinary schwannomas are very rare, especially primary bladder schwannomas. They account for only 0.1% of bladder tumours. The literature reports that simple surgical resection has a good effect and prognosis.

CASE PRESENTATION

A 39-year-old man had no significant improvement in symptoms due to frequent urination and urgency for 1 month following the treatment of prostatitis for 2 weeks. Ultrasound and computed tomography (CT) showed a mass in the left side wall of the bladder (size approximately 2.0 × 1.9 cm) that had clear boundaries and protruded outward from the bladder. After the extraperitoneal space was dilated with a balloon, a minimally invasive laparoscopic partial cystectomy was performed in this space to remove the tumour. The pathological diagnosis was bladder schwannoma. Immunohistochemical staining showed that it was strongly S100 protein positive. There was no recurrence after 2 years follow-up by cystoscopy and CT.

CONCLUSIONS

Bladder schwannomas are clinically rare benign bladder lesions and no specific clinical manifestations. Laparoscopic partial cystectomy through the extraperitoneal space is a safe and feasible treatment option.

Clinicopathological study of gastric schwannoma and review of related literature

BACKGROUND

This study aimed to investigate the clinical features, diagnostic criteria, treatment options, and prognosis of patients with gastric schwannoma (GS).

METHODS

We collected the clinical data of all patients pathologically diagnosed with GS in Zhejiang Provincial People's Hospital from May 2012 to October 2021.

RESULTS

A total of 26 cases of GS were analyzed clinicopathologically, where the sizes of the tumor were found to be in the range of 1-6 cm (mean: 3.16 cm, median: 3.05 cm). A computed tomography (CT) scan analysis revealed that most masses were either moderately progressive or uniformly enhanced. According to ultrasound gastroscopy results, most of them were hypoechoic masses. There were 23 cases of surgery and three cases of endoscopic submucosal tumor dissection. Immunohistochemistry demonstrated that S100 was positive in 26 patients, immunomarker SOX10 was positive in five, whereas CD34, CD117, and SMA were negative in most patients. CK (Pan), Dog-1, and Desmin were also found negative. All 26 cases were followed up after the conclusion of the study where no evidence of recurrence or metastasis was observed.

CONCLUSIONS

GS is a unique form of peripheral schwannoma. The diagnosis of this type of tumor depends on the pathology and immunohistochemistry of the individual. The key to treating this type of tumor is endoscopy and surgery. Follow up and related literature review showed that GS was a benign tumor with little possibility of malignant transformation.

Deep Learning-Based Ultrasound Combined with Gastroscope for the Diagnosis and Nursing of Upper Gastrointestinal Submucous Lesions

The study focused on the diagnostic value of deep learning-based ultrasound combined with gastroscope examination for upper gastrointestinal submucous lesions and nursing. A total of 104 patients with upper gastrointestinal submucous lesions diagnosed in hospital were selected as the research subjects. In this study, the feed forward denoising convulsive neural network (DnCNN) was improved, and the n-DnCNN model was designed and applied to ultrasonic image processing. The peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) of Gaussian filtering, NL-means, and DnCNN were then compared with n-DnCNN. Subsequently, the distribution and types of submucosal lesions in different parts of the upper digestive tract were analyzed by ultrasound combined with gastroscope and gastroscope examination alone, and the diagnostic performance of this method was evaluated. The results showed that the average PSNR and SSIM of the n-DnCNN model were 33.01 dB and 0.87, respectively, which were significantly higher than GF, NL-means, and DnCNN algorithms, and the difference was statistically significant ( $P<0.05$ ). Of the 116 lesions detected, 49 were located in the esophagus (42.24%), 52 in the stomach (44.83%), and 15 in the duodenum (12.93%). Of the 49 esophageal submucosal lesions, 6.12% were located in the upper esophagus, 55.1% in the middle esophagus, and 38.79% in the lower esophagus, and the difference was statistically significant ( $P<0.05$ ). Of the gastric submucosal lesions, the lesions in the gastric cardia were significantly less than in other parts, and the difference was statistically significant ( $P<0.05$ ). The accuracy of ultrasound combined with gastroscope in the diagnosis of upper gastrointestinal submucous episodes was 82.32%, higher than that of gastroscope examination, and the difference was statistically significant ( $P<0.05$ ). In conclusion, the n-DnCNN model has a good noise reduction effect, and the obtained image is of high quality. Ultrasound combined with gastroscope examination can effectively improve the accuracy of diagnosis of upper gastrointestinal submucous lesions.

The necessarity of treatment for small gastric subepithelial tumors (1-2 cm) originating from muscularis propria: an analysis of 972 tumors

BACKGROUND AND OBJECTIVES

Up till now, there are still controversies about the specific indication of endoscopic resection for small gastric subepithelial tumors (gSETs) originating from muscularis propria. We aimed to investigate the safety of endoscopic resection and postoperative pathology analysis.

METHOD

The patients with primary small gSETs originating from muscularis propria, treated by endoscopic resection in the endoscopic center of Shengjing Hospital between January, 2011 and September, 2019 were enrolled. The complete resection rate, adverse events and clinicopathological features were recorded.

RESULT

A total of 936 patients with 972 gastric SETs ≤ 2 cm originating from muscularis propria were included in our study. All the lesions were successfully treated by endoscopic resection. Nearly half of lesions were proved to be gastrointestinal stromal tumor (GIST) [n = 411 (42.3%)] according to postoperative pathology. All the objects were further subdivided into 2 groups, ≤ 1 cm, > 1 and ≤ 2 cm gSETs. The risk of gastric GIST of intermediate/high risk in the group (> 1 and ≤ 2 cm gSETs) is 8.41 times as that of gastric GIST in the group (the size of gastric ≤ 1 cm gSETs) (P < 0.05).

CONCLUSION

Endoscopic resection is a safe and effective treatment for small gSETs. gSETs (1-2 cm) is more risky than gSETs (≤ 1 cm) and should be resected. This should be evaluated by further studies.

Endoscopic versus surgical resection in the management of gastric schwannomas

BACKGROUND AND AIMS

Gastric schwannoma (GS) is not well clinically recognized and surgical resection (SR) remains the mainstay of treatment. Recently, endoscopic resection (ER) appears to be a safe and effective alternative. However, its comparative outcomes with SR is lacking. Our aim was to first compare clinical outcomes and costs between ER and SR in the management of GSs.

METHODS

A total of 46 consecutive patients with GSs who underwent ER (n = 16) or SR (n = 30) in our large tertiary center between July 2007 and Oct 2018 were included. Clinicopathologic features, clinical outcomes, medical costs and follow-up were retrospectively reviewed and compared between two groups.

RESULTS

Baseline characteristics are comparable except for a smaller tumor size in ER group (22.9 vs 41.0 mm, p = 0.002). Complete resection was achieved in 87.5% of patients with ER and 100% of patients with SR (p = 0.116). The ER group had a significant shorter operative time (91.6 vs 128.2 min), less blood loss (16.9 vs 62.7 mL) and lower operation cost (21,054.4 vs 30,843.4 RMB) than SR group (all p < 0.05). There was no significant difference in adverse events (12.5% vs 10%, p = 0.812) and length of postoperative hospital stay (8.3 vs 8.2 days, p = 0.945). During a long-term follow-up of mean 37.4 months (range 6-140 months), no residue, recurrence or metastasis was observed in both groups.

CONCLUSIONS

Compared with SR, ER has the similar safety and efficacy in the management of GSs, but contributes to a shorter operation time and lower medical costs. ER may be considered as the first-line treatment, especially for patients with GSs smaller than 30 mm.

What About Gastric Schwannoma? A Review Article

PURPOSE

Gastric schwannomas (GSs) are rare mesenchymal neoplasms of the gastrointestinal tract. Diagnosis is often achieved postoperatively, based on pathology reports of retrieved specimens. The aim of the present study is to follow up all patients with gastric schwannoma (Gs) undergoing endoscopic, partial, or more extended surgery and to evaluate the appearance of local or distant recurrence.

METHODS

A PubMed, Cochrane, and Embase systematic review of the literature has been performed. Original papers, review articles, and case reports published between 1988 and 2019 were considered eligible. All the studies who met the inclusion criteria were analyzed. Statistical analysis of data has been performed using GraphPad Prism 7 software.

RESULTS

Three hundred twenty-eight articles were found, and a total of 102 were included and analyzed in depth. Fifty-three papers reported the follow-up information, ranging from 1 to 417 months across different studies. Among them, 31 patients underwent endoscopic removal of the gastric lesions; 140 patients underwent local surgery, including wedge resection or partial gastrectomy; and 148 patients underwent subtotal or total gastrectomy. The median follow-up was of 27-38-33 months, respectively. No recurrence or distant metastasis was detected in the endoscopy group. Among local surgery group, liver metastasis was reported in one case; in extended surgery group, one patient died for multiple liver metastases.

CONCLUSIONS

Local or more extended surgery involved a larger cohort of patients and reported satisfactory long-term results compared with endoscopy group. Surgery in absence of a definite preoperative diagnosis is considered the gold standard treatment for resectable Gs.

Gastric schwannoma: a case report and literature review

BACKGROUND

Gastric schwannoma is a rarely seen gastric tumor accounting for only 0.2% of all gastric tumors. It is difficult to distinguish a gastric schwannoma from other gastric tumors preoperatively.Case presentation: A 30-year-old man with no significant medical history or physical examination findings presented with a 1-month history of right upper abdominal discomfort. The preoperative diagnosis was a gastrointestinal stromal tumor, but the postoperative pathologic and immunohistochemical examinations confirmed a gastric schwannoma. The patient underwent laparoscopic wedge resection of the stomach without additional postoperative treatment, and his postoperative recovery was uneventful. No recurrence or metastasis was found at the 2-year follow-up examination.

CONCLUSION

Although gastric schwannomas are usually not malignant, they are difficult to distinguish from other malignant stromal tumors preoperatively. Surgical resection should be recommended when a schwannoma is malignant or considered to be at risk of becoming malignant.

Endoscopic submucosal excavation and endoscopic full-thickness resection for gastric schwannoma: five-year experience from a large tertiary center in China

BACKGROUND AND AIMS

Endoscopic resection (ER) is an effective and safe method for gastric submucosal tumors, mostly composed of gastrointestinal stromal tumors and leiomyomas. The role of ER in gastric schwannoma (GS) has rarely been described. Our aim was to evaluate the efficacy and safety of ER for GS.

METHODS

This is a retrospective study in consecutive patients who underwent ER for GS from March 2013 to October 2018 at our center. Clinicopathological, endoscopic, and follow-up data were collected and analyzed.

RESULTS

A total of 16 consecutive patients (9 females, 56.3%) were included, with a mean age of 50.4 years (range 25-75 years). The mean tumor size was 22.9 ± 15.1 mm (range 10-55 mm). Thirteen tumors (81.3%) were located in the middle third of the stomach and 12 tumors (75%) grew with intraluminal pattern. Endoscopic submucosal excavation (ESE) was performed in 7 patients while endoscopic full-thickness resection (EFTR) was done in 9 patients. R0 resection was achieved in 14 patients (87.5%). The mean operative time was 91.6 ± 52.8 min (range 36-203 min) and the mean postoperative length of hospital stays was 8.3 ± 2.7 days (range 6-13 days). No adverse events were encountered except for fevers in 2 patients. No patients required surgical resection or intervention. During long-term follow-up of mean 21.8 months (range 6-62 months), no residue, recurrence, or metastasis was observed.

CONCLUSIONS

ER is effective and safe for patients with GS with favorable long-term outcomes.

Clinical Characteristics and Surgical Management of Gastrointestinal Schwannomas

OBJECTIVES

Schwannomas are tumors arising from Schwan cells of the neural sheath. Gastrointestinal schwannomas (GS) are rare and easily confused with a heterogeneous group of neuroectodermal or mesenchymal neoplasms. The aim of the present study is to analyze the clinicopathological features, surgical management methods, and long-term prognoses of GS patients.

METHODS

Between August 2004 and July 2019, 51 patients with GS were treated at the Peking Union Medical College Hospital. The medical records were reviewed retrospectively. A database containing demographic characteristics, clinical symptoms, imaging tests, operation details, pathological results, and prognoses was constructed and analyzed.

RESULTS

GS accounted for 2.0% of all schwannomas. The cohort comprised 19 men (37.3%) and 32 women (62.7%). The mean age was 55.7 ± 11.4 years. The most common symptom was abdominal pain (29.4%). Twenty-seven patients (52.9%) were asymptomatic and diagnosed incidentally. The most common tumor location of GS was the stomach (90.2%). S-100 had the highest positive rate (100%) in immunohistochemical staining. Forty-six patients (90.2%) were followed-up at a mean period of 49.5 ± 41.4 months. Forty-four patients (95.7%) survived without tumor, 1 patient survived with tumor, and 1 patient died. The 5-year cumulative overall survival rate and cumulative disease-free survival rate were 97.5% and 95.2%, respectively.

CONCLUSION

GS are rare gastrointestinal tumors with favorable prognoses after surgical resection. Stomach is the most common site. Definitive diagnosis is determined by postoperative pathology. S-100 expression has diagnostic significance.

A Rare Case of Gastric Schwannoma: A Case Report and Literature Review

In general, schwannoma is a benign and slow-glowing neoplasm that rarely occurs in the gastrointestinal tract as a submucosal tumor (SMT), with the most common site being the stomach. As gastric schwannoma (GS) is a rare tumor, there is limited data in the literature about its clinical features. The diagnosis of schwannoma can only be made by pathological examination with positive staining for S-100 protein. It is necessary to obtain an accurate diagnosis to introduce optimal treatment options preoperatively. However, a precise diagnosis of GS is difficult, even with modern imaging techniques. On the other hand, a complete resection with a negative surgical margin (R0) of GS is considered the best treatment, with an excellent prognosis. We present a case of a 66-year-old female patient who underwent laparoscopic-assisted wedge gastrectomy for gastric SMT, pathologically diagnosed as GS, with positive staining for S-100 protein and negative for c-kit and CD34. At 12-month follow-up after surgery, there was no recurrence or metastasis of GS. Our treatment is appropriate and effective in case of GS exceeding 50 mm.

Digital image analysis-based scoring system for endoscopic ultrasonography is useful in predicting gastrointestinal stromal tumors

BACKGROUND

When gastric mesenchymal tumors (GMTs) measuring 2-5 cm in size are found, whether to undergo further treatment or not is controversial. Endoscopic ultrasonography (EUS) is useful for the evaluation of malignant potential of GMTs, but has limitations, such as subjective interpretation of EUS images. Therefore, we aimed to develop a scoring system based on the digital image analysis of EUS images to predict gastrointestinal stromal tumors (GISTs).

METHODS

We included 103 patients with histopathologically proven GIST, leiomyoma or schwannoma on surgically resected specimen who underwent EUS examination between January 2007 and June 2018. After standardization of the EUS images, brightness values, including the mean (Tmean), indicative of echogenicity, and the standard deviation (TSD), indicative of heterogeneity, in the tumors were analyzed.

RESULTS

Age, Tmean, and TSD were significantly higher in GISTs than in non-GISTs. The sensitivity and specificity were almost optimized for differentiating GISTs from non-GISTs when the critical values of age, Tmean, and TSD were 57.5 years, 67.0, and 25.6, respectively. A GIST-predicting scoring system was created by assigning 3 points for Tmean ≥ 67, 2 points for age ≥ 58 years, and 1 point for TSD ≥ 26. When GMTs with 3 points or more were diagnosed as GISTs, the sensitivity, specificity, and accuracy of the scoring system were 86.5%, 75.9%, and 83.5%, respectively.

CONCLUSIONS

The scoring system based on the information of digital image analysis is useful in predicting GISTs in case of GMTs that are 2-5 cm in size.

Incidental Finding of Gastric Schwannoma in a Renal Failure Patient - Managed by a Minimally Invasive Procedure: Report of a Rare Case

BACKGROUND Schwannomas are benign tumors originating from any nerve with a Schwann cell sheath. It is an extremely rare tumor, accounting for 0.2% of all gastrointestinal tumors and 4% of all benign tumors of the stomach. Clinical differentiation of gastrointestinal mesenchymal tumors is challenging and confirmatory diagnosis requires biopsy. Surgical resection is the treatment of choice when tumor size is less than 30 mm or when it is located within the muscularis propria. Here, we present a case of a large (>50 mm) gastric Schwannoma that was resected using a new laparoscopic technique suitable for larger tumors. CASE REPORT A 69-year-old woman with past medical history of hypertension, diabetes mellitus, and stroke, and CKD stage 4, presented to the Emergency Department (ED) with persistent nausea, vomiting, and weakness. She was found to have uremia requiring emergent hemodialysis. Eventually, she underwent peritoneal catheter insertion for peritoneal dialysis. A mass on the gastric antrum was found incidentally during the procedure. Biopsy confirmed the diagnosis of gastric Schwannoma. The tumor was removed successfully using a minimally invasive procedure via robotic-assisted laparoscopy. CONCLUSIONS Gastric Schwannoma is a rare submucosal tumor arising from Auerbach's plexus in the muscularis propria. It is usually asymptomatic, but can present with symptoms such as epigastric pain, or upper gastrointestinal bleeding. Tissue biopsy and immunohistochemical staining are the criterion standard for diagnosis. It has no tendency for malignant transformation. Tumors smaller than 30 mm are removed endoscopically, while tumors larger than 30 mm can be removed surgically. In this case, the tumor was removed successfully by minimally invasive robotic-assisted laparoscopy.

Gastrointestinal schwannomas: a rare but important differential diagnosis of mesenchymal tumors of gastrointestinal tract

BACKGROUND

Schwannomas of gastrointestinal tract are rare, mostly benign and notably different neoplasms from conventional schwannomas that arise in soft tissue or the central nervous system. These tumors are of clinical importance since they should always be considered in the differential diagnosis of submucosal lesions of gastrointestinal tract.

METHODS

Seven patients with a pathologically proven gastrointestinal schwannoma were identified in our series of mesenchymal tumors and reviewed retrospectively. Clinicopathological and immunohistochemical parameters along with the follow-up results were analysed.

RESULTS

The series included two males and five females, with a mean age 69 years (range, 39-81). Most patients were asymptomatic on presentation, except for two patients with abdominal pain. In the other cases (n = 5), the tumor was an incidental finding during other medical, imaging or surgical procedures. The tumors were located in the stomach (n = 4) and in the small intestine (n = 3) with an average size of 29 mm (range, 12-70). A preoperative diagnosis was achieved only in one case with a CT-guided core biopsy. Otherwise the clinical, intraoperative, endoscopic or radiological findings were unspecific. Patients with gastric tumor underwent either laparoscopic (n = 2) or open (n = 2) gastric wedge resection of the tumor; in the cases of intestinal tumor (n = 3) a segmentectomy was performed. Pathological examination revealed solid homogenous tumors, which were highly cellular and composed of spindle cells with positive staining for S100 protein, and confirmed the diagnosis of schwannoma. All tumors were negative for c-Kit, smooth muscle actin, desmin and DOG-1 and showed very low proliferation index. There were negative resection margins and no malignant variants were recognized. At an average follow-up of 60 months (range, 24-185) all patients were free of disease with no signs of recurrence or metastases and acceptable gastrointestinal function.

CONCLUSIONS

Schwannomas are rare, slow-growing and mostly asymptomatic gastrointestinal mesenchymal tumors. They are difficult to be diagnosed preoperatively as endoscopic and radiological findings are nonspecific but histological and immunohistochemical features are of paramount importance to differentiate between benign and malignant schwannomas, or other spindle cell sarcomas. The treatment of choice is complete surgical excision without a conclusive preoperative diagnosis, and the long-term outcome is excellent as these lesions are mostly benign.