A Rare Cause of Acute Pancreatitis in a Patient with Neurofibromatosis Type 1

Abstract

Pancreatic neurogenic tumors are an extremely rare cause of abdominal pain and do not typically cause acute pancreatitis. We report a case of 37 year-old female with history of Neurofibromatosis 1 (NF1) who presented to the hospital with acute onset epigastric abdominal pain for two days. On laboratory evaluation she was found to have mildly elevated lipase. She had no history of alcohol use or family history of pancreatitis. An abdominal CT showed the presence of a heterogeneous inflammatory mass and surrounding stranding within the uncinate process of pancreas and associated acute thrombosis of superior mesenteric vein (SMA), as well as thrombosis of right portal vein (figure 1). Based on these findings a diagnosis of acute pancreatitis was made. She then underwent abdominal MRI which confirmed presence of a 3.4 cm mass adjacent to uncinate process (Figure 2). It was also noted that mass was encasing the thrombosed SMA, and MRI characteristics of mass suggested the diagnosis of neurofibroma. Evaluation with endoscopic ultrasound and biopsy confirmed diagnosis of pancreatic neurofibroma. Patients with NF1 have increased risk of neoplasms throughout the body. There are five categories of abdominal neurogenic neoplasms in NF1: neurofibroma, plexiform neurofibroma, malignant peripheral nerve sheath tumor, triton tumor and ganglioneuroma. Majority (65%) of neurofibromas are asymptomatic and 10% are associated with presence of NF1. Gastrointestinal involvement is most common in the stomach and jejunum, involvement of retroperitoneum, pancreas, and hepatobiliary tract is extremely rare. Clinical manifestations are dependent on location and extent of lesion, as neurofibromas frequently infiltrate into adjacent tissue. In addition to symptoms, malignant transformation is rare but a potentially serious complication (1.8 - 1.9%). In our patient, the neurofibroma was located contiguous to pancreas and infiltrating SMA resulting in thrombosis of SMA as well as portal vein making definitive management very challenging. This case demonstrates very rare etiology of abdominal pain in patient with known neurofibromatosis. At this time, there is not a consensus on the management of retroperitoneal and pancreatic neurofibromas. Serial imaging evaluation and prompt surgical intervention is required if mass has malignant characteristics.Figure 1Figure 2