Discussion
IVC aneurysms are uncommon. It is only 54 cases reported in English medical literature (1).The etiologies of IVC aneurysms remain unclear, but in some acquired cases of IVC aneurysms trauma and inflammatory processes are involved as causative factor. In addition, longstanding systemic venous hypertension secondary to right side heart failure, tricuspid valve lesions, cardiomyopathy, and constrictive pericarditis may also contribute to the formation of IVC aneurysms. Moreover, IVC aneurysms have been associated with embryogenic malformation such as tetralogy of Fallot, azygous agenesis, membranous IVC obstruction and left side IVC (1, 2, 4).
An aneurysm of IVC may present with the symptoms related to complications such as thromboembolism or IVC syndrome or may have some nonspecific abdominal or back pain. Although, uncomplicated aneurysm of IVC may have no symptoms (1, 2, 4, 6). In our case, it was the diarrhea, abdominal pain and lower extremity venous insufficiency which lead us to the diagnosis. Imaging studies such as MRI angiography, CT angiography and venography are diagnostic (2, 3, 4). Duplex ultrasonography is also helpful. According to Gradman and Steinberg classification of IVC aneurysms our case is a type III IVC aneurysm (5). Type II-IV IVC aneurysms have high rate of complications such as thromboembolism and rupture (1, 2, 3).
Management of IVC aneurysms entirely depends on their nature and presence of complications (1, 3, 6). In our case we proceeded to perform surgical resection of aneurysm because there was a high risk of complications and there was a low probability of surgical complications. The endovascular approach was discussed but was rejected because of the risk of IVC rupture in case of huge oversizing of the endograft (in order to avoid any endoleak). Moreover, a septic cause of the pseudo aneurysm was not excluded.
In our case we did not find any past history of trauma. Additionally, histopathologic and bacteriologic examinations of aneurysmal tissue biopsy did not find any particular abnormality in favor of inflammatory process and complementary examinations did not find any associated congenital malformation. Therefore we presumed our case as spontaneous (idiopathic).