Thrombosed Hepatic Artery Aneurysm in the setting of Acute Pancreatitis
Visceral artery aneurysms are infrequent lesions among other vascular diseases with an incidence of 0.01-2% in autopsy and angiographic procedures. Hepatic artery aneurysm (HAA) is a rare pathology with less than 500 cases reported in the literature and account for nearly 20% of all visceral artery aneurysms. They are the second most common visceral artery aneurysm after splenic artery aneurysm. Today, about half of the HAA are iatrogenic. Atherosclerosis, collagen disorders, trauma, inflammation, infection or vasculitis are other usual predisposing factors. Most of the HAA are asymptomatic and 60-80% of the cases are diagnosed when the aneurysm has complicated with rupture or with obstructive jaundice due to external compression of the biliary ducts. Of the reported cases of HAA so far, vascular pancreatitis related complications occur following sever pancreatitis e.g. necrotizing pancreatitis. We present an unusual patient who had acute none sever pancreatitis which causes the growth and thrombosis formation in a preexisting smaller aneurysm. A 20-year-old woman presented with history of icterus from four days ago followed by epigastric and left upper quadrant abdominal pain. She had low grade fever during that period of time. In her medical history, there was no evidence of hospitalization, surgery or clinical conditions including hepatobiliary or gastrointestinal tract disorders. The laboratory tests showed a white blood cell count (WBC) of 10.2 g/L (neutrophil: 80%), aspartate aminotransferase (AST) 160 U/L, alanine aminotransferase (ALT) 400 U/L, alkaline phosphatase 630 U/L, total and direct bilirubin 7.3 and 6.8 μmol/L respectively, amylase 62 U/L, lipase 250 U/L and CRP 77 mg/l. Ultrasound detected an aneurismal dilation in the hepatic artery with mural thrombosis (Figure 1.) as well as dilation of the intra and extra hepatic biliary ducts secondary to mass effect of the aneurysm on the porta hepatis. On Color Doppler, this aneurysm was characterized by swirling flow within it in a characteristic yin-yang pattern (Figure 2.). The abdominal CT scan with contrast revealed a 55 mm × 35 mm aneurysm of the hepatic artery that contained mural thrombus in the aneurysmal sac (Figure 3.) as well as gallbladder wall thickening. Based on our patient clinical manifestations and laboratory tests, she had acute none severe pancreatitis. However, it is not reasonable that the aneurysm was formed secondary to mild pancreatitis. We can conclude this way that she had acute none sever pancreatitis (without specific imaging evidences) which might have played a prominent role in the pathophysiology of the growth and thrombosis formation in a preexisting smaller HAA. Gallbladder wall thickening is also explained by pericholecystic inflammation resulting from pancreatitis .