Gastric Schwannomas Misdiagnosed as GIST: A Comparative Study of Clinic Strategies Based on Membrane Marker Detection

Abstract

: Gastric schwannomas are one of the rarest gastric tumors originating from the nerve plexus of the gut wall. Because most of these tumors don’t have any specific symptom and the majority of gastric mesenchymal tumors are gastrointestinal stromal tumors (GISTs), many are therefore misdiagnosed as GISTs. In addition, gastric schwannoma is the benign and slow-growing lesion in the stomach, but GISTs had poor outcomes due to lack of response to nonsurgical interventions. In our study, we analyzed two cases of these tumors. Computer tomography (CT), contrast-enhanced CT, gastroscopy, endoscopic ultrasonography (EUS) were applied to diagnose these two patients. In addition, histological examination and immunohistochemistry (IHC) were used to confirm the final diagnosis. All imageological examination such as CT, contrast-enhanced CT, gastroscopy and EUS, diagnosed these two patients as gastrointestinal stromal tumors. Surprisingly, after the subtotal gastric surgery, histological examination showed that these lesions were composed of spindle cells. Those cells presenting in the bundle or fence-like arrangement were mildly heterologous. The outcomes of immunohistochemistry of the cell membrane markers (CD117 / DOG-1 negative, CD34 mild positive or negative) were the exact opposite of the characteristic presentation of GIST. These pathological findings refused the primary diagnosis, and were in coincidence with the characteristics of gastric schwannomas. To our best knowledge, these tumors are really rare that only two cases could be reported and analyzed clinically. CT and EUS could help diagnose gastric schwannomas before pathological examination results, but in order to define this diagnosis correctly. Pathological examination and IHC staining should be applied after surgery. To avoid the recurrence, it is better to resect the lesion completely, regardless of the malignant or benign disease.