pseudoaneurysm- a uncommun complication of pancreatitis

Clinical History

A fifty years old man presented with complaint of epigastric pain for one month. Patient had no complaints of hemetemesis or maelena. Patient was taking alcohol since last 25 years.

Imaging Findings

A fifty years old man presented with complaint of epigastric pain for one month. Patient had no complaints of hemetemesis or maelena. Patient was taking alcohol since last 25 years. US examination of abdomen was performed at our institute which revealed changes of chronic pancreatitis in the head of pancreas with presence of well-defined anechoic cystic lesion with hyperechoic margins below head of pancreas. Color-Doppler ultrasound indicates the vascular nature of the mass CT Scan of upper abdomen shows changes of chronic pancreatitis in form of specks of calcification and irregular margins with presence of well defined heterogeneous and hypodense lesion just below the head of the pancreas. The lesion had parietal calcification. Contrast CT images show complete contrast filling of the lesion with surrounding hypondensity. Thus diagnosis of pseudoaneurysm with partial thrombosis was considered. The patient was scheduled for selective angiography that confirmed the diagnosis of pancreaticodudenal pseudoaneurysm and embolization was done.

Discussion

An uncommon but important complication associated with chronic pancreatitis is formation of pseudoaneurysm. It is known to have very low incidence up to 10%. The most common artery affected by pseudoaneurysm is splenic artery. Next in the frequency are gastroduodenal and pancreaticodudenal arteries followed by left gastric, hepatic and small intrapancreatic arteries. Although patient may develop palpable epigastric mass, bleeding and pain, they are often fully asymptomatic. The pathogenesis of these aneurysms is poorly understood. There are probably two types of aneurysms associated with pancreatitis although they cannot be differentiated. If the inflammatory process causes partial digestion of arterial wall with loss of elastic tissue, it results in focal dilatation of vessel forming true aneurysms. False aneurysms are thought to occur due to incorporation of artery within wall of pseudocysts; with digestion of the artery wall the vessel ruptures into the pseudocyst converting it into pseudoaneurysm. The presence of pseudoaneurysm is mostly suspected on grey-scale US scan, while color-Doppler ultrasound successfully indicates the vascular nature of the mass. Typical grey-scale US features of pseudoaneurysm include anechoic mass with posterior acoustic enhancement, possibly with hyperechoic margins   Typical CT finding of pseudoaneurysm include a well-defined mass with a hyperdense centre that shows contrast enhancement and a less dense periphery corresponding to mural clot and fibrous wall. Angiography is fundamental for confirming diagnosis and exact location of aneurysm. Although occasional reports have alluded to the spontaneous thrombosis of some pancreatic pseudoaneurysms, the current consensus holds that all these malformations should be treated to prevent the complication of bleeding. Nonsurgical management consists of transarterial catheter angioembolization with or without endoscopic stent placement. Angioembolization is considered much less invasive than surgery. It also allows the performance of surgery under optimal conditions. Surgical approach is another modality of treatment.  

Differential Diagnosis List

Final Diagnosis

pancreaticodudenal pseudoaneurysm

URL:	https://eurorad.org/case/4661
DOI:	10.1594/EURORAD/CASE.4661
ISSN:	1563-4086