(448) Intraductal Papillary Mucinous Neoplasm Manifesting as Recurrent Acute Pancreatitis

Introduction: Intraductal papillary mucinous neoplasm, or IPMN, is the mucin-producing subtype of pancreatic cystic lesions that can manifest as recurrent acute pancreatitis and is frequently mistaken for pancreatic pseudocyst.

Description: A 67-year-old Caucasian male was admitted to the hospital with epigastric abdominal pain for two days without any fever, nausea, or vomiting. Laboratory investigation showed calcium 9.5 mg/dL, lipase 240 units/L, triglyceride 135 mg/dL, and bilirubin 0.4 mg/dL with normal liver enzymes. The patient was clinically diagnosed with acute pancreatitis. Approximately a month prior, he was admitted to the hospital for acute pancreatitis. He had no alcohol intake for two years before his presentation. He had a cholecystectomy three years prior. CT abdomen and pelvis with contrast showed a 1.6 x 1.2 cm pancreatic cyst within the pancreatic head. MRI of the abdomen with and without contrast showed a well-defined 1.3x 1.2 cm pancreatic uncinate process focus, communicating with the main pancreatic duct. After the patient was treated for acute pancreatitis, endoscopic ultrasound (EUS) and ERCP were performed. The EUS revealed a 0.61 cm x 1.3 cm complex, thick-walled, septated cystic lesion in the uncinate process. ERCP demonstrated that the pancreatic orifice had fishmouth deformity. The patient ultimately underwent pancreatoduodenectomy for the treatment of IPMN.

Discussion: IPMN constitutes approximately 25% of cystic neoplasms of the pancreas. Patients with IPMN can present with epigastric discomfort or pain, weight loss, nausea, and vomiting. According to a systematic review, 12%-67% of patients with IPMN can develop acute pancreatitis. Pancreatic cystic lesions following a recent episode of pancreatitis are commonly thought to be due to pseudocyst formation, which can delay the diagnosis of IPMN. Identifying an IPMN in recurrent acute pancreatitis is crucial since it has the potential for malignant transformation. MRI with magnetic resonance cholangiopancreatography (MRCP) is the imaging modality of choice. EUS is more sensitive than MRI or CT scans in distinguishing between neoplastic and non-neoplastic cysts. Due to the possibility of progression to malignancy, lifelong periodic surveillance and surgical treatment for lesions with worrisome features is necessary.