SCHWANNOMA: A RARE PANCREATIC NEOPLASM

BackgroundPancreatic schwannomas are rare neoplasms, which typically affect the adult population. The size of these tumors is highly variable. Since two thirds of these tumors are partially cystic, they grossly mimic cystadenomas and cystadenocarcinomas of the pancreas. The most common presenting symptom is abdominal pain. However, weight loss, jaundice and gastrointestinal bleeding have all been reported. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary initial imaging modalities, which suggest schwannomas by evidence of encapsulation, hypointensity on T-1 weighted images and hyperintensity on T-2 weight images. However, the diagnosis is typically made at the time of laparotomy following biopsy. Histologically, schwannomas are characterized by spindle cells, whorling appearances and strong immunoperoxidase staining with S-100 protein marker. Surgical resection is the mainstay of therapy.MethodsIn the present report, we discuss a case of a 69 year-old woman whose initial presentation was progressive worsening abdominal pain in the epigastric and left upper quadrant. The patient had no systemic symptoms and laboratory results including tumor markers were negative. A CT scan of the abdomen showed a large mass arising from the head of the pancreas. Subsequent needle biopsy revealed a mass consistent with schwannoma.ResultsAt laparotomy, a large retroperitoneal mass, 5.0×4.4cm, at the head of the pancreas was found to encase the superior mesenteric artery, and portal vein confluence. Frozen biopsy confirmed benign schwannoma. Curative resection was deferred due to extensive vascular involvement and favorable tumor biology. A retro-colic gastrojejunostomy was performed and radiation therapy was instituted post-operatively.ConclusionPancreatic schwannomas are extremely uncommon and only 23 cases had been previously reported. Definitive diagnosis is obtained with routine histology and immunoperoxidase staining. Most tumors are benign and surgical resection is curative. Malignant transformation, albeit rare, had been reported. The role of chemoradiation therapy in the management of schwannomas is still unclear.