Gastric Schwannoma - A Rare Cause of Dyspepsia Esther Cha MD, Shadi Al-Bahri MD, Patrick Domkowski, MD, FACS, Jason Radecke MD, FACS Department of Surgery, Medstar Union Memorial Hospital, Baltimore, Maryland INTRODUCTION DISCUSSION Schwannomas, also known as neurinomas, are generally benign tumors arising from the Schwann cells of cranial and spinal nerve roots. Gastrointestinal schwannomas are rare benign neoplasms that are distinctively unique compared to soft-tissue and central nervous system mesenchymal neoplasms. The most common symptoms include abdominal pain, dyspepsia, gastrointestinal bleeding, and an abdominal mass. We present a case report of a gastric schwannoma causing severe gastric reflux symptoms that was treated successfully by laparoscopic partial gastrectomy in complete en bloc removal. Schwannomas are rare tumors arising from Schwann cells that cover peripheral nerves. Most commonly presenting as acoustic neuromas, they represent 9% of primary brain tumors. They rarely present in the GI tract, most commonly the stomach – although it represents only 0.2% of all gastric tumors. Large intestinal or retroperitoneal schwannomas are extremely rare. Although typically asymptomatic, they may present with symptoms such as pain, dyspepsia, bleeding or mass effect resulting in early satiety. Gastric schwannomas lack encapsulation as they originate from the dispersed autonomic nerve Schwann cells. Typical features include atypical spindle cells and S100 protein positivity. Accurate preoperative diagnosis of gastrointestinal schwannomas is often difficult, as it can only be made definitively with IHC staining. On CT scan, they typically demonstrate well- demarcated and homogeneous features. EUS guided fine needle aspiration or biopsy can be performed. They are, however, often misdiagnosed as malignant GIST by EGD, EUS and PET/CT imaging. Surgical resection is considered the treatment of choice. Axial (above) and sagittal (below) views of the pedunculated lesion noted on the medial aspect of the lesser curve of the stomach. The mass projects intra-luminally which explains the potential for early satiety, reflux and pain. METHODS 42 year old male with severe reflux symptoms without other associated symptoms. He denied night sweats, fever, chills, or unintentional weight loss. An esophagogastroduodenoscopy (EGD) revealed smooth normal gastric mucosa and a pedunculated lesion arising from the incisura suggestive of a gastrointestinal stromal tumor (GIST). A preoperative contrast-enhanced computed tomographic (CT) scan was obtained which demonstrated a heterogeneous mass along the lesser curve. The patient underwent a laparoscopic resection. The mass was located on the medial aspect of the lesser curvature of the stomach and was thus able to be resected by partial wedge gastrectomy avoiding a Billroth II or Roux-en-Y reconstruction. Surgical pathology with IHC staining was consistent with a gastric schwannoma (S100 positive, CD117 negative). CONCLUSION Schwannomas are rarely observed in the gastrointestinal tract. Preoperative diagnosis is often difficult and challenging to distinguish from other mesenchymal tumors. Definitive treatment includes complete surgical excision with negative margins. The outcome after surgery is excellent as these neoplasms are generally benign in nature.