Introduction Pancreaticoduodenal artery aneurysms (PDAs) are infrequent, comprising less than 2% of visceral aneurysms. Complicated cases are even less common and this case report exemplifies the diagnostic and therapeutic complexities unique to this clinical problem. Case Presentation A 73-year-old man presented to hospital with acute onset right sided abdominal pain and syncope. Computed tomography (CT) and angiogram showed large retroperitoneal haematoma (19cm wide) with no active bleeding. He was observed for three days and discharged with a plan for follow up. He represented to hospital a further three days later with gastric outlet obstruction and was transferred to a tertiary level institution for further management.Repeat CT angiogram demonstrated a tight stenosis of coeliac trunk with an aneurysm evident in the pancreaticoduodenal artery. He underwent pancreaticoduodenal arcade collateral aneurysm embolization successfully. He is currently being follow up by vascular outpatient clinic for consideration of coeliac axis stenting. Conclusion PDA presentations are broad, ranging from incidental radiological discovery though to abdominal pain and/or life-threatening haemorrhage. Ruptures of pancreaticoduodenal artery aneurysms can be lethal, with a mortality risk of 49% attributed to bleeding into the retroperitoneal space, abdominal cavity or gastrointestinal tract. While surgery was traditionally the primary treatment modality for pancreaticoduodenal artery aneurysms, rapid advancements in interventional radiology have facilitated the safe and effective performance of transcatheter arterial embolization. In cases of spontaneous retroperitoneal bleeding, clinicians should remain mindful of the potential for a PDA.