A case of pancreaticoduodenal artery aneurysm causing pancreatic pseudotumour and duodenal obstruction.

This case report describes a ruptured pancreaticoduodenal artery aneurysm (PDAA) causing pancreatic pseudotumour and duodenal obstruction. A 59-year-old man was referred to our hospital with a chief complaint of frequent vomiting without abdominal pain. Because a mass lesion 10 cm in diameter was palpated in the right para-umbilical region and found in the head of the pancreas on computerized tomography (CT) and ultrasonography, malignant tumour of the pancreas or tumour-forming pancreatitis was strongly suspected, and further examination was performed.Magnetic resonance imaging (MRI) results suggested subacute haematoma inside the mass. On angiography, an aneurysm 8 mm in diameter was found in the posterior superior pancreaticoduodenal artery (PSPD). Since an ultrasound-guided percutaneous needle biopsy from the solid part of the mass indicated no malignancy, the lesion was considered an inflammatory pseudotumour in the head of pancreas due to ruptured aneurysm. Bypass surgery was planned, but the tumour shrank significantly with conservative treatment. Obstruction disappeared completely without surgery 4 weeks after the first symptom.