GP183 Achieving the panacea in diagnosing paediatric autoimmune pancreatitis – a case study

Introduction Both in the Republic of Ireland and worldwide paediatric autoimmune pancreatitis (P-AIP) is very rare and its incidence is largely unknown. To date, a few anecdotal cases in Ireland have been diagnosed histopathologically following resection of a pancreatic mass. Case Report We report the case of a 13yo boy admitted to the paediatric ward with a 4 day history of jaundice and pruritus, and a 2 day history of pale loose stools, dark urine, and vomiting. On examination he also had right upper quadrant abdominal tenderness. His liver profile showed biochemical signs of obstructive jaundice and cholestasis. He had a normal amylase and only mildly raised lipase. Total immunoglobulin level and IgG4 were normal. Transabdominal ultrasound showed a distended gallbladder and a dilated CBD of 15 mm. MRCP showed a possible 3cm mass in the head of pancreas (HOP) with a normal pancreatic duct. Our paediatric unit is within an adult hospital with subspecialist pancreatobiliary (PB) expertise including endoscopic ultrasound (EUS). EUS showed that the entire pancreas was expanded and no discrete mass was seen in the HOP. A EUS-guided fine needle biopsy (FNB) was performed. An ERCP was performed in the same session with insertion of a double pigtail stent into the CBD. However over the following days the patient remained icteric. Histological samples were reviewed by both the adult and paediatric histopathology departments. The FNB specimens showed benign acinar groups and predominantly neutrophilic inflammatory infiltrate, acinar inflammation and fibrosis. There was no positive IgG4 staining in the few plasma cells. Once prednisolone was commenced the patient clinically and biochemically improved. A diagnosis of acute autoimmune pancreatitis was made. Discussion P-AIP presents with very different clinical and biochemical signs compared to adult type. This case report discusses the challenging issue of diagnosing P-AIP in Ireland and worldwide. Currently in Ireland there is no dedicated paediatric EUS service. International expert group consensus statements recommend that ideally P-AIP be confirmed by well-described and pathognomonic histopathological features in a pancreatic biopsy. This case report demonstrates how paediatric patients can benefit from adult subspecialist PB expertise allowing further radiological and histopathological information to achieve a definitive diagnosis of P-AIP. It is important that paediatricians and paediatric surgeons in Ireland and abroad be aware of the benefits of this collaboration in the P-AIP setting.