False pancreas divisum: a complication of post-endoscopic retrograde pancreatography pancreatitis.

Pancreas divisum (PD) and meandering main pancreatic duct (MMPD) are common developmental variants of the pancreatic ductal system. They always appear in the head of the pancreas and are associated with idiopathic pancreatitis. The condition of these variants is rarely reported to have changed after birth. We present a rare case of false PD that occurred with alteration of loop-type MMPD after endoscopic retrograde pancreatography (ERP) and brush cytology followed by post-procedural pancreatitis. A 76-year-old female underwent pre-surgical ERP and brush cytology for an incidentally detected, expanding branch-type intraductal papillary mucinous neoplasm in the body of pancreas. The guidewire was inserted along the main pancreatic duct (MPD) and had uncoiled the loop-shaped MPD into a linear shape; soon afterwards, the patient developed post-procedural acute pancreatitis. Follow-up magnetic resonance cholangiopancreatography study 1 month later revealed the morphology of PD with an absent ventral duct. We hypothesize that inflammatory synechia had occluded the uncoiled ventral duct. This single case provides evidence that pancreatic ductal anatomy is flexible in some situations.