Enlarging Pancreatic Schwannoma - A Case Report and Review of the Literature

Context Schwannomas are rare neoplasms that typically occur in the peripheral nerve of the extremities. Visceral localization of these tumors is particularly rare. We present a unique case of a pancreatic schwannoma presenting as long-lasting dyspepsia and intermittent epigastric pain. Case report Seventy-two-year-old female presented with dyspepsia for 2 years and an incidental mass in the head of the pancreas on abdominal CT scan. Patient had multiple negative endoscopic ultrasound guided biopsies and a non-diagnostic open core biopsy. She was followed up for 3 years with serial imaging until an abdominal CT scan showed an increase in size of the pancreatic mass from 1.9x2.2 cm to 3.1x2.7 cm. Physical examination was unremarkable. Laboratory tests including tumor markers were normal. Given the enlarging size of the mass and its impingement on the portal vein, the consensus was to proceed with surgery. Patient underwent a non pylorus preserving pancreaticoduodenectomy. Histology revealed a 3.5 cm mass showing a spindle cell neoplasm with mild atypia. The lesion was well defined and nerve tissue was noted at the periphery. On immuno stains, the spindle cells were positive for S-100 protein and negative for pancytokeratin, CD-34, CD-117, smooth muscle actin and Melan A, consistent with the diagnosis of a prancreatic schwannoma. Conclusions Pancreatic schwannomas arise from branches of the vagus nerve which courses through the pancreas. Pre-operative diagnosis of pancreatic schwannomas is difficult even with multiple imaging modalities. The final diagnosis of these tumors is often made only after operative excision and histological studies.