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.

Gastric GIST or gastric schwannoma-A diagnostic dilemma in a young female

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Gastric Schwannoma is a rare neoplasm of stomach.

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It mimic clinically and radiologically with Gastric GIST.

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Immunohistochemical study can differentiate these two tumors.

Introduction

Gastrointestinal stromal tumor (GIST) is the commonest mesenchymal tumor of GI tract and 60–70% of it seen in the stomach, whereas Gastric schwannoma is a benign, slow growing and one of the rare neoplasms of stomach. Age distribution, clinical, radiological features and gross appearance of both tumors are similar.

Presentation of case

We report a rare case of gastric schwannoma in a 20-year-old girl, who underwent subtotal gastrectomy with the suspicion of a GIST preoperatively but later confirmed to be gastric schwannoma postoperatively after immunohistochemical study.

Discussion

Accordingly, the differential diagnosis for gastric submucosal mass should be gastric schwannoma. Furthermore, Gastric schwannoma is a benign neoplasm with excellent prognosis after surgical resection, whereas 10–30% of GIST has malignant behavior. Therefore, it is important to distinguish between gastric schwannoma and GIST so as to make an accurate diagnosis for optimally guide treatment options.

Conclusion

Due to the paucity of gastric schwannoma, the index of suspicion for this diagnosis is low. So it is important to include gastric schwannoma in the differential diagnosis when preoperative imaging studies reveal submucosal exophytic gastric mass and after resection of the tumor with a negative margin, it should be sent for immunohistochemical study for confirmation of diagnosis.

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.

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.

Gastric schwannoma exhibiting increased fluorodeoxyglucose uptake

This is the first case of gastric schwannoma that exhibited increased accumulation of [(18)F] fluorodeoxyglucose (FDG) on positron emission tomography (PET) imaging. The patient was a 60-year-old woman in whom esophagogastroduodenoscopy showed a submucosal tumor, about 25 mm in size, in the upper body of the stomach, with ulceration at the top of the tumor. Endoscopic ultrasonography revealed a well-defined hypoechoic mass located in the proper muscle layer of the stomach. The specimen taken from the tumor showed only inflammatory degenerative tissue. Abdominal computed tomography revealed a tumor in the upper body of the stomach. FDG-PET showed FDG uptake (standardized uptake value [SUV] max 5.8) coincident with the tumor. Hence, the tumor was diagnosed initially as a gastrointestinal stromal tumor of the stomach. Laparoscopic partial gastrectomy was performed. Pathological examination showed that the tumor consisted of spindle cells with large nuclei, and mitosis was absent. The Ki-67 labeling index of the tumor cells was 4%. Immunohistochemically, the tumor cells showed a positive reaction for S-100 protein, whereas they were negative for KIT, CD 34, and alpha-smooth muscle actin protein. The tumor was diagnosed as a benign gastric schwannoma. Gastric schwannoma should be included in the differential diagnosis of submucosal tumors of the stomach with FDG uptake.