Clinicopathological and Immunohistochemical Characterisation of Gastric Schwannomas in 29 Cases

Lijun Zheng,Lijin Feng,Zhen Yu,Bin Xu,Jiafu Ji,Xiaojiang Wu,Chunqiu Chen,Ziyu Li,Zhaode Bu,Martin E Kreis

doi:10.1155/2014/202960

Abstract

Schwannomas are tumors arising from the nervous system that also occur infrequently in the gastrointestinal tract, most commonly in the stomach. This report characterizes 29 patients with benign or malignant gastric schwannomas. Surgical data and clinical follow-up information were available for 28 cases with a median postoperative duration of 57 months. Clinicopathological and immunohistochemical characteristics of benign and malignant schwannomas were analysed. Four cases (13.7%) were histologically diagnosed with malignant schwannoma. All tumors were positive for S-100 and CD56 proteins, displaying a diffuse staining pattern. Vimentin was expressed in 100% cases and all schwannomas were negative for smooth muscle actin, c-kit, and HMB-45. A significant difference was observed between the group of benign and malignant schwannomas as regards recurrences and metastasis after complete resection (P = 0.015). The survival time of patients with benign schwannomas was longer than the malignant group (P = 0.013), so gastric malignant schwannomas have a potential for recurrence and metastasis, with subsequently short survival. Complete resection with an attempt to remove all tumor tissue with negative margins is of paramount importance in the management of gastric schwannomas, particularly when they turn out to be malignant.

Highlights

Schwannomas, known as neurinomas or neurilemmomas, are tumors of spindle cells originating from any nerve that has a Schwann cell sheath
Vimentin was expressed in 100% cases and all schwannomas were negative for smooth muscle actin, c-kit, and HMB45
The survival time of patients with benign schwannomas was longer than the malignant group (P = 0.013), so gastric malignant schwannomas have a potential for recurrence and metastasis, with subsequently short survival

Summary

Introduction

Schwannomas, known as neurinomas or neurilemmomas, are tumors of spindle cells originating from any nerve that has a Schwann cell sheath. Schwannomas of the gastrointestinal tract are very rare tumors, with the stomach being the most common location. The incidence of gastric schwannoma is reported to be about 0.2% of all gastric tumors and 4% of all benign gastric neoplasms [1]. Gastric schwannomas are thought to arise from the sheath of Auerbach’s plexus or, less commonly, from Meissner’s plexus [2, 3]. The common presenting symptom is upper gastrointestinal bleeding and a palpable mass [4]. The differentiation of a schwannoma from other submucosal tumors often creates preoperative diagnostic challenges. The definite diagnosis of gastric schwannoma requires histological testing to be positive for the S-100 protein, CD56, CD57, and vimentin but negative for both smooth muscle actin and c-KIT [3]

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