Digestive tract schwannoma

A rare case of schwannoma of the small intestine discovered during intussusception

A woman in her 60s with anemia was diagnosed with a small intestinal intussusception on computed tomography. She underwent a double-balloon endoscopy, which revealed submucosal tumor in the ileum. Suspected to be the cause of anemia and intussusception, surgical intervention was carried out, revealing it to be a schwannoma. Schwannomas of the small intestine are very rare, and because exophytic growths are common, intussusception due to luminal side development is even rarer.

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.

Schwannoma of the Small Intestine

Schwannomas of the gastrointestinal tract are rare. Herein, we report a case of schwannoma originating from the small intestine. A 78-year-old woman underwent medical follow-up after surgery for bladder cancer, and a mass in the upper part of the pelvis was revealed by abdominal CT. With the diagnosis of a submucosal tumor of the small intestine, she underwent partial intestinal resection. The submucosal tumor was pathologically composed of S100-positive spindle cells and diagnosed as schwannoma. We report this case of rare schwannoma of the small intestine and review the literature.

Gastric Schwannoma: A Tumor Must Be Included in Differential Diagnoses of Gastric Submucosal Tumors

Gastric schwannoma (GS) is a rare neoplasm of the stomach. It accounts for 0.2% of all gastric tumors and is mostly benign, slow-growing, and asymptomatic. Due to its rarity, GS is not widely recognized by clinicians, and the precise differential diagnosis between GS and other gastric submucosal tumors remains difficult preoperatively. The present study reports a case of GS misdiagnosed as gastrointestinal stromal tumor and reviews the clinical, imaging, and pathological features, treatment, and follow-up of 221 patients with GS previously reported in the English literature. Although GS is rare, the case reported in the current study highlights the importance of including GS in differential diagnoses of gastric submucosal tumors. Furthermore, the findings of the review suggest that although many cases are asymptomatic, the most common symptoms are abdominal pain or discomfort, not gastrointestinal bleeding, and malignant GSs present with clinical symptoms more commonly. Although large-sample multicenter studies on the efficacy, safety, and oncological outcomes of minimally invasive techniques are required, the findings presented herein may be helpful for clinicians when diagnosing or treating GS.

Benign mesocolon schwannoma in PET/CT and immunohistochemistry assessment: a case report

Schwannoma is a common soft tissue tumour, but it appears to be very rare in the gastrointestinal tract. Benign schwannoma develops extremely rarely in the mesocolon, with only 2 patients reported in the literature. A 75-year-old woman was admitted to our Department of Oncological Surgery with an abdominal mass, which was discovered incidentally during abdominal ultrasound examination. Positron emission tomography/ computed tomography imaging with the use of 18F-fluorodeoxyglucose (FDG PET/CT) showed an abnormal mass in the upper right abdomen with the presence of diffuse FDG uptake. A laparotomy revealed an encapsulated, non-invasive mesocolon tumour in the hepatic flexure region. Definitive diagnosis was confirmed by the histopathological examination of the postoperative preparation. Immunohistochemical staining confirmed benign mesocolon schwannoma. Previous cases indicate that schwannomas in the mesocolon are benign tumours. Our patient had a good prognosis even after enucleation treatment. Although schwannomas are very rare and generally asymptomatic, the differential diagnosis of schwannomas and gastrointestinal stromal tumours is important for practical purposes.

Gastric schwannoma: a clinicopathologic study of 51 cases and critical review of the literature

Schwannoma is a rare gastrointestinal mesenchymal tumor, as the vast majority of gastric mesenchymal tumors are gastrointestinal stromal tumors. In this study, we analyzed clinicopathologically 51 gastric schwannomas. These tumors predominantly occurred in older adults with a marked female predominance (40 women and 11 men; median and mean ages, 60 and 58 years). They variably presented with gastric discomfort, bleeding, or rarely gastric outlet obstruction; and many were incidental findings during other medical procedures. The tumors ranged from 1 to 10.5 cm (median, 4.5 cm). The typical histologic features included spindle cells usually with microtrabecular architecture and focal nuclear atypia, and peritumoral lymphoid cuff, whereas features of soft tissue schwannomas, such as encapsulation, nuclear palisading, vascular hyalinization, and dilatation, were absent or infrequent. Median mitotic count was 2/50 high-power fields, with the highest count being 13/50 high-power fields. No malignant variants were recognized, and long-term follow-up did not reveal recurrences or metastases. Immunohistochemically, all examined tumors were S100 protein positive and most were also GFAP positive, whereas CD34 and NF68 were encountered rarely and all tumors were negative for HMB45, KIT, DOG1/Ano 1, smooth muscle actin, desmin, and synaptophysin. None of the 9 tumors studied contained gastrointestinal stromal tumor-specific KIT or PDGFRA mutations. Fluorescence in situ hybridization studies revealed multiple signals with BCR probe (chromosome 22) and centromeric probes for chromosomes 2 and 18 suggesting polyploidy. These findings indicate that gastric schwannoma is a distinctive form of peripheral nerve sheath tumor that in many ways differs from soft tissue schwannoma. It should be distinguished from gastrointestinal stromal tumor and other mesenchymal tumors of the gastrointestinal tract, such as the S100 protein-positive gastrointestinal clear cell sarcoma and metastatic melanoma.

Hypervascular subepithelial gastrointestinal masses: CT-pathologic correlation

Although the vast majority of gastrointestinal (GI) masses are epithelial neoplasms, a variety of subepithelial masses are infrequently encountered during endoscopic or radiologic examination. A subepithelial mass, which was previously called a submucosal mass, is defined as a mass covered with normal-appearing mucosa, whether the underlying process is intramural or extramural in origin. At contrast material-enhanced computed tomography (CT), hypervascular subepithelial masses are usually detected more easily than isoattenuating or hypovascular masses. Entities that appear as intramural hypervascular subepithelial lesions include neuroendocrine tumors, GI stromal tumor, glomus tumor, hemangioma, angiosarcoma, Kaposi sarcoma, nerve sheath tumors, hypervascular metastases, heterotopic tissues, and vascular structures. Entities that appear as extramural hypervascular subepithelial lesions include Castleman disease, solitary fibrous tumor, inflammatory myofibroblastic tumor, and actinomycosis. Some rare gastric cancers resemble subepithelial tumors. In comparison with endoscopic ultrasonography, CT is of limited value in differentiating the layers of the GI wall and determining the origin of mass lesions. However, recent advances in multidetector CT with multiplanar reformation allow one to determine whether a GI mass is of epithelial, intramural subepithelial, or extramural subepithelial origin. Furthermore, the full extent of tumors can be delineated, and local invasion and distant metastases can be identified. Familiarity with the characteristic CT appearances of hypervascular subepithelial masses of the GI tract will help radiologists make a more confident diagnosis.

Gastric Schwannoma Presenting as an Incidentaloma on CT-Scan and MRI

A 67 year old female was referred because of an incidentaloma on CT-scan and MRI which showed a 5.0 cm large mass in the wall of the distal stomach. After an initial work-up which suggested a gastrointestinal stromal tumor (GIST), a partial gastrectomy with a Billroth II gastrojejunostomy was performed. The histological diagnosis was a schwannoma. Gastric schwannomas are rare tumors which comprise 0.2% of all gastric tumors and 4% of all benign gastric neoplasms with a peak of incidence in the 4th and 5th decade of life. Gastric schwannomas are usually asymptomatic, but can present with ulceration and/or gastrointestinal bleeding. Clinical, endoscopical, surgical, radiological and histological features of this case are described and the relevant literature is reviewed.

Intraabdominal schwannomas: a single institution experience

INTRODUCTION

Intraabdominal schwannomas are rare, benign tumors. This study presents a single institution experience with 12 such tumors.

METHODS

Between 1991 to 2006, 12 patients with a pathologically proven intraabdominal schwannoma were identified from a series of 216 mesenchymal tumors and were reviewed retrospectively.

RESULTS

There were nine females and three male patients with a median age of 58 years (range 35-88 years). Eleven patients were symptomatic, and the tumors were located in the stomach (n = 8), jejunum, colon, rectum, and lesser sac. Multiple preoperative investigations including endoscopies with biopsies and computed tomography (CT) scans were performed, but none yielded a correct definitive preoperative diagnosis. The median tumor size was 52 mm (range 18-95 mm). Pathological examination demonstrated the 11 gastrointestinal tract (GIT) schwannomas to be solid homogenous tumors, which were highly cellular and were composed of spindle cells with positive staining for S100 protein. The pathological appearance of the lesser sac schwannoma was distinct as it demonstrated cystic degeneration with hemorrhage and Antoni A and B areas on microscopy typical of soft tissue schwannomas. All 12 patients were disease-free at a median follow-up of 22 months (range 1-120 months).

CONCLUSION

Intraabdominal schwannomas are rare tumors, which are most frequently located within the GIT. GIT schwannomas are difficult if not impossible to diagnose preoperatively as endoscopic and radiologic findings are nonspecific. The treatment of choice is complete surgical excision because of diagnostic uncertainty, and the long-term outcome is excellent as these lesions are uniformly benign.