The Role of Endoscopic Ultrasound in Diagnosing Solid Pseudopapillary Epithelial Neoplasm (SPEN) of the Pancreas in a Pediatric Patient

Abstract

Solid pseudopapillary epithelial neoplasm (SPEN) of the pancreas is a rare tumor that accounts for less than 2% of exocrine pancreatic tumors affecting non-Caucasian females in the second and third decades of life. We describe a rare case of SPEN presenting in a Caucasian pediatric patient. A 12-year-old Caucasian female with no past medical history presented with three weeks of intermittent right upper quadrant and epigastric abdominal pain associated with nausea and vomiting. She was found to have a leukocytosis, elevated amylase, lipase and alkaline phosphatase initially concerning for pancreatitis. Non-contrast CT scan demonstrated a well-circumscribed lesion and a mildly dilated gallbladder with mass effect causing gastric outlet obstruction. Contrast MRI demonstrated a 7.8 x 7.5 cm encapsulated mass arising from the pancreatic head with prominent solid, cystic and hemorrhagic components with an enhancing capsule. Endoscopic ultrasound (EUS) was performed demonstrating an 8.1 x 6.8 cm mass in the peripancreatic-periduodenal region and EUS-guided fine needle biopsy (FNB) was performed using a 19-gauge core needle with a through-the-needle Moray biopsy forceps. Pancreatic FNB showed normal pancreatic acini among blood and degenerative cells. Malignancy was ruled out and biopsy findings were consistent with SPEN. She underwent pancreaticoduodenectomy and cholecystectomy. Her post-operative course was uneventful and she was discharged home. Pathology of the pancreatic mass showed a solid and pseudopapillary neoplasm of the pancreas with extensive necrosis (90%) and benign pancreatic tissue with focal chronic inflammation. SPEN of the pancreas may present with vague abdominal pain and/or a gradually enlarging abdominal mass. These neoplasms are typically large at the time of diagnosis with an average size of 8 cm. The tumor often presents in the pancreatic tail with varying degrees of hemorrhage, cystic changes, or necrosis. In our patient, the mass arose from the head of the pancreas. Generally, SPEN are rare tumors with low malignant potential and complete surgical resection is typically curative. EUS-guided fine needle biopsy helps in establishing tissue diagnosis and helps to facilitate a care plan for surgical resection.Figure: Contrast MRI with a 7.8 x 7.5 cm encapsulated mass with prominent solid, cystic and hemorrhagic components with an enhancing capsule.Figure: EUS with a 8.1 x 6.8 cm mass in the peripancreatic-periduodenal region.