What About Gastric Schwannoma? A Review Article

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-Two Unusual Cases with Usual Presentation and Review of Literature

Schwannomas, also known as neurilemmomas, are characteristically benign, slow growing neoplasms originating from Schwann cell sheath. Gastrointestinal schwannomas are very rare with stomach being the most affected organ representing approximately 0.2% of all gastric tumours. Malignant transformation is rarely reported in these tumors and complete surgical resection with negative margins is the recommended treatment. Herein, we report our experience of 2 cases of gastric submucosal spindle cell tumour (SMT), which were preoperatively assumed to be as gastrointestinal stromal tumor (GIST), however postoperatively confirmed as schwannoma on immunohistochemical examination.

Gastric schwannoma: Two case reports and review of the literature

Gastric schwannomas are rare, slow-growing tumors whose clinical presentation is nonspecific. These are mostly benign, with a low probability of malignant transformation and an excellent prognosis. We present 2 cases of gastric schwannomas with distinct clinical features and imaging patterns, whose therapeutic approach differed. Case 1 is a 73-year-old woman with a voluminous subepithelial lesion in the greater gastric curvature, with predominantly endoluminal growth. Clinically the patient presented with nonspecific abdominal complaints and underwent complete surgical excision. Case 2 is a 69-year-old woman with an exophytic lesion adjacent to the gastric antrum, diagnosed incidentally and managed conservatively, with imaging follow-up, for the last 5 years and stable ever since. This article aims to focus on this rare disease, illustrating its main imaging findings, particularly in magnetic resonance imaging, along with pathological correlation, as well as reviewing the literature, discussing the differential diagnosis, and exploring clinical management and prognosis.

Gastric schwannoma diagnosing gastric stromal tumor

A 45-year-old male visited our hospital for a medical examination without any clinical complaints. The patient had an gastroscopy, which revealed a 30mm*30mm hemispherical submucosal tumor arising from the lesser curvature of the gastric body , suggesting a gastrointestinal stromal tumor (GIST) as a preoperative diagnosis;Endoscopic resection was determined to be the best choice and the patient underwent a endoscopic full-thickness resection and endoscopic purse-string suture. Except for a slight low fever, the patient was well recovered and was discharged on his 7th post-operation. Pathological analysis and immunohistochemical staining showed fascicular growth of neoplastic Schwann cells and confirmed the diagnosis of gastric schwannoma through high positivity for S-100 protein.

Gastric Schwannoma: A Rare Subepithelial Lesion of the Stomach

Gastric schwannomas (GS) are rare, slow-growing, benign subepithelial (SE) lesions of the stomach. These are difficult to differentiate preoperatively from other types of SE lesions, as the gross appearance and clinical presentation are very similar especially the gastrointestinal stromal tumors (GISTs), which are the most common SE lesions of the stomach. We present the case of a 35-year-old Asian man with a one-month history of intermittent, right, upper quadrant pain and hematemesis. Preoperatively, intravenous contrast-enhanced computer tomography scan (CECT) showed a well-circumscribed lesion in the upper abdomen closer to the stomach's lesser curvature. Endoscopic ultrasound revealed an ulcerated subepithelial lesion and subsequent biopsy with a 22-gauge fine-needle biopsy (22G FNB) needle confirmed the diagnosis of GS. The patient underwent distal gastrectomy and a Bilroth 1 procedure. The postoperative biopsy was consistent with the initial one, therefore supporting the diagnosis of gastric schwannoma. Postoperatively, the recovery remained uneventful.

Schwannoma: A Rare Case of Submucosal Gastric Tumor

Schwannoma is a tumor that originates from the Schwann cells that surround a neuron's axon. This tumor is very rare in the gastrointestinal tract and develops submucosally from intestinal nerve plexuses. The most common location for gastrointestinal schwannomas is the stomach, where they account for only 0.2% of gastric tumors. We present the case of a 56-year-old asymptomatic patient who was diagnosed, following a routine ultrasound examination, with an abdominal tumor. An abdominal MRI confirmed the gastric origin of the tumor. Although a subsequent upper-digestive endoscopic ultrasound was performed, a definitive diagnosis could not be established. Thus, a laparoscopic wedge resection of the stomach was performed. The immunohistochemical examination of the tumor established the diagnosis of benign schwannoma. Despite the availability of advanced endoscopy and imaging techniques, the diagnosis of gastric schwannoma is very rarely preoperative. The immunohistochemical identification of S-100 on the surgical specimen confirmed the diagnosis.

Recurrence of gastric schwannoma

Gastric schwannoma can be malignant in 13.8% of cases. The prognosis of malignant schwannoma is usually poor, characterized by a rapidly progressive disease course and a poor response to chemotherapy. Normally, the recurrence of schwannoma is due to involvement of the surgical resection margin. In turn, recurrence of malignant gastric schwannoma GS is approximately 50%, 25% locoregional and 25% with liver metastases. Even after a complete gastric resection with associated lymphadenectomy, schwannoma may present liver metastases during follow-up.

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.

Natural history of gastrointestinal schwannomas

Background and study aims  Data are lacking on the natural history of gastrointestinal tract schwannomas. We aimed to study the natural history of all gastrointestinal schwannomas including location, diagnosis, management, and long-term outcomes. Patients and methods  Patients with a pathological diagnosis of gastrointestinal schwannoma between January 2000 and March 2020 were identified. Data on baseline demographics, presentations, associated malignancies, malignant transformation, treatment, and recurrence were collected. Results  Our cohort consisted of 44 patients with a mean age of 58.6 years, with 63.6 % women and 84.1 % White. The stomach (38.6 %) was the most common location followed by the colorectum (31.8 %). Only 22.7 % of patients were symptomatic and 22.0 % had a personal history of other malignancies. Tissue diagnosis was obtained via endoscopy in 47.7 % and from surgical pathology in 52.3 %. On histology, 65.9 % of the tumors were solid, 11.4 % had mixed features, and 2.3 % had necrosis. SP100 was tested in all but one patient and was positive in all. Mean Ki-67 in 12 patients with tumors measuring ≥ 2 cm was 3.0 % indicating a low proliferation rate. Of the patients, 77.3 % had surgery and 18.2 % underwent endoscopic resection. At a mean follow-up of 5.0 ± 4.31 years, there was no malignant transformation, recurrence or mortality associated with gastrointestinal schwannomas. Conclusions  Gastrointestinal schwannomas are diagnosed in the fifth to sixth decade with predominance in women and Whites. They are benign, mostly asymptomatic, and diagnosed incidentally. Asymptomatic gastrointestinal schwannomas including lesions ≥ 2 cm in size do not appear to need further monitoring or intervention. Patients with them should be counseled to remain up to date with routine screening guidelines pertaining to the colon, breast, and lung cancer due to the high incidence of concomitant malignancy.

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.

Artificial intelligence-based diagnosis of upper gastrointestinal subepithelial lesions on endoscopic ultrasonography images

BACKGROUND

Endoscopic ultrasonography (EUS) is useful for the differential diagnosis of subepithelial lesions (SELs); however, not all of them are easy to distinguish. Gastrointestinal stromal tumors (GISTs) are the commonest SELs, are considered potentially malignant, and differentiating them from benign SELs is important. Artificial intelligence (AI) using deep learning has developed remarkably in the medical field. This study aimed to investigate the efficacy of an AI system for classifying SELs on EUS images.

METHODS

EUS images of pathologically confirmed upper gastrointestinal SELs (GIST, leiomyoma, schwannoma, neuroendocrine tumor [NET], and ectopic pancreas) were collected from 12 hospitals. These images were divided into development and test datasets in the ratio of 4:1 using random sampling; the development dataset was divided into training and validation datasets. The same test dataset was diagnosed by two experts and two non-experts.

RESULTS

A total of 16,110 images were collected from 631 cases for the development and test datasets. The accuracy of the AI system for the five-category classification (GIST, leiomyoma, schwannoma, NET, and ectopic pancreas) was 86.1%, which was significantly higher than that of all endoscopists. The sensitivity, specificity, and accuracy of the AI system for differentiating GISTs from non-GISTs were 98.8%, 67.6%, and 89.3%, respectively. Its sensitivity and accuracy were significantly higher than those of all the endoscopists.

CONCLUSION

The AI system, classifying SELs, showed higher diagnostic performance than that of the experts and may assist in improving the diagnosis of SELs in clinical practice.

Combined laparoscopic-endoscopic “rendez-vous” procedure in a case of gastric Schwannoma in a toddler

Introduction. Schwannomas are rare benign tumors of the gastrointestinal tract. Despite the differences in features of schwannomas located in the stomach as opposed to peripheral or soft tissue schwannomas, their immunohistochemical characteristics are the same. We present a case of a 14-month-old boy with a gastric tumor who underwent a combined laparoscopic-endoscopic resection surgery, followed by gastric schwannoma diagnosis. Case outline. The patient was admitted to our pediatric hospital with a fever of unknown origin. Endoscopy, performed after recurrent hematemesis, revealed an ulcer in the gastric antrum. At the four-week follow-up, gastroscopic and microscopic findings were normal. Two weeks later, a flank mass in the antrum was detected by an ultrasound examination. A new gastroscopy and CT scan confirmed the presence of a tumor-like mass, 5 cm in diameter. A combined laparoscopic-endoscopic polypectomy was performed with a necessary conversion for complete resection of tumor. The initial histological findings were consistent with a gastrointestinal stromal tumor. Due to this tumor?s rarity in childhood, the paraffin-embedded tissue samples were referred for a second opinion. Histological and immunohistochemical characteristics of the tumor made the gastrointestinal stromal tumor diagnosis unlikely and consistent with a completely resected gastric schwannoma. No recurrence of the disease occurred during the seven-year follow-up. Conclusion. Combined laparoscopic-endoscopic surgery is a feasible and effective treatment for large gastric tumors that cannot be excised endoscopically. Schwannoma should be included in the differential diagnostic consideration of gastric tumor lesions even in childhood.

Endoscopic full-thickness resection of a gastric schwannoma

A 69-year-old man was referred to our center for further evaluation and treatment of a gastric mass. Esophagogastroduodenoscopy found a 30-mm submucosal tumor (SMT) in the gastric body. Endoscopic ultrasound revealed a hypoechoic lesion originating from the muscularis propria layer.