CT And MRI Manifestations Of Gastric Schwannoma And Analyse The Pathological Basis

Background:Schwannoma is a benign tumor of nerve sheath cells.It is one of the most common benign peripheral nerve tumors.It occurs mostly in the head,neck,trunk,extremities and other major nerve trunks.It is located in the posterior mediastinum and retroperitoneum.Neurilemmoma originated from the gastrointestinal tract is very rare.Gastric schwanaoma(GS)belongs to gastrointestinal mesenchymal tumors,accounting for 3%of all gastrointestinal mesenchymal tumors.The stomach is the most common site,accounting for 0.2%of all gastric tumors[1,2].It is often misdiagnosed as gastric stromal tumors and other mesenchymal tumors before operation.The disease is benign and the incidence of malignant probability is very low.In recent years,with the increasing number of reports on gastric schwannoma,most of them are mainly CT images,MRI images are rarely introduced.The etiology of gastrointestinal stromal tumors(GIST)is lack of clinical specificity and is not easy to be diagnosed before operation.Gastric schwannoma,gastrointestinal stromal tumor and leiomyoma were not differentiated by pathology in the past,but with the development of pathology and immunohistochemistry,gastric schwannoma can be differentiated from other mesenchymal tumors.The pathological features of all 24 cases of gastric schwannomas were analyzed and compared with CT and MRI images,which can help the imaging physicians understand the imaging manifestations and pathological basis of gastric schwannomas more clearly.By studying the CT and MRI features of gastric schwannoma and analyzing its pathological basis,it is of great significance to the early diagnosis and accurate treatment of gastric schwannoma,and provides more information for clinical operation and preoperative evaluation,especially the multi-plane and multi-angle analysis of the relationship between the lesion and the surrounding tissues on MRI,and provides information for clinical preoperative treatment.More security.Objective:To investigate the computerized tomography(CT)and magnetic resonance imaging(MRI)manifestations of gastric schwannoma(GS),analyse the pathological basis,and thereby to better understand GS and improve its diagnosis.It is helpful for the early diagnosis,treatment and prognosis of gastric schwannoma,gastric stromal tumors,gastric leiomyoma and other difficult to differentiate diseases on imaging.Methods:CT and MRI manifestations of 24 GS cases confirmed by surgery and pathology in Beilun People's Hospital and Beilun First Affiliated Hospital of Zhejiang University from August 2012 to December 2015 were retrospectively analyzed.All the 24 cases underwent plain and enhanced abdominal CT scan,11 of them were confirmed by operation and pathology.MR scan and enhanced examination were also carried out.All 24 cases underwent gastric mass resection and pathological examination.All cases were diagnosed and analyzed by more than two doctors,and the pathological findings were summarized and analyzed to explore the pathological basis of gastric schwannoma.Results:All 24 GS tumors are round or oval solid masses with smooth edges.The locations include gastric fundus(1 case),gastric body(21 cases)and gastric antrum(2 cases).Five tumors grew inwards gastric cavity,9 tumors grew outwards gastric cavity while 10 tumors grew towards both directions.Thirteen tumors displayed superficial ulcer on gastric eminence.20 cases have homogeneous density,remarkable mucoid degeneration,different degrees of cystic change,and annular calcification were found in 20,1,2 and 1 cases,respectively.The contrast-enhanced scanning showed displayed moderate enhancement in 21 cases and apparent enhancement in 3 cases.Conclusion:Gastric Schwannoma should be considered if CT scanning shows a round or oval tumor located in gastric wall with smooth edge and homogeneous density,and contrast-enhanced scanning shows a delayed and gradual enhancement and superficial ulcer in gastric eminence.Without obvious bleeding,calcification,necrosis on plain scan,and the lesions can protrude into the cavity and outside.After enhancement,the arterial phase did not or slightly enhanced,the venous phase was slightly or moderately enhanced,the delayed phase was moderately or significantly enhanced,the enhancement process was gradual enhancement,the peak of enhancement appeared in the delayed phase,the lesions were homogeneous,cystic degeneration and necrosis was rare,and the formation of intraluminal ulcer,the possibility of gastric schwannoma should be considered.