Introduction: Pancreatic cancer is very rare in the pediatric population. Incidence data is scarce, and few case reports have been published. Pancreatic ductal adenocarcinoma (PDA) is the most common subtype in adults, but is rare in children. We report a case of a benign pancreatic head mass in a pediatric patient initially diagnosed as PDA on endoscopic ultrasound (EUS) guided biopsy.
Case Description/Methods: A 13-year-old male with past medical history of treated Helicobacter pylori infection 6 months prior was admitted for severe acute intermittent epigastric pain. Labs showed elevated transaminases and gamma-glutamyl transferase. Abdominal ultrasound demonstrated an indeterminate solid mass-like lesion of 3 cm at the pancreatic head, and the common bile duct (CBD) was dilated to 0.9 cm. Magnetic resonance cholangiopancreatography showed a 2.2 cm indeterminate lesion along the pancreatic head region with dilated CBD of 1.4 cm, tapering at the level of the lesion. On hospital day 3, the patient underwent esophagogastroduodenoscopy and EUS. A parenchymal mass of 2.2 cm was visualized in the head of pancreas, and fine needle biopsy was performed. Cytology diagnosis was well differentiated ductal adenocarcinoma. Serum carcinoembryonic antigen, carbohydrate antigen 19-9, and alpha-fetoprotein were all normal. The patient underwent elective Whipple procedure. Surprisingly, no malignancy was identified on the surgical specimen. Instead the findings supported a diagnosis of localized fibrosing pancreatitis with high background of immunoglobulin G4 with interlobular pattern. Patient was discharged home on post-operation day 13. EUS cytology was reviewed at a tertiary cancer center and later reported as acute on chronic inflammation without malignancy.
Discussion: Despite increased use of EUS for diagnosis of pancreatic masses, 5-10% of patients who undergo Whipple procedure for presumed malignancy will have benign pathology: most commonly chronic fibrosing pancreatitis, chronic pancreatitis, or focal active pancreatitis. The false positive rate for diagnosing malignancy using EUS-fine needle aspiration (FNA) of solid pancreatic lesions is less than 1%. However, it may be higher in pediatrics as the prevalence of PDA is much lower in adults. For suspected cases of PDA in pediatric patients, additional review of EUS cytology at an experienced and dedicated cancer institution is advisable before further intervention to prevent the medical and psychosocial ramifications of a false positive cancer diagnosis.
