Misinterpretation of a giant idiopathic concealed right iliac artery aneurysm as infantile pelvic tumor imaged by non-angiographic computed tomography: a case report

Background
Idiopathic pediatric artery aneurysm is extremely rare and sometimes behaves like a pelvic neoplasm. As it is associated with a high mortality while ruptured, the accurate diagnosis is indispensable to avoid life-threatening complications. Angiographic imaging is the gold standard for diagnosis and treatment planning of the aneurysm. Due to the considerably higher radiation sensitivity of children, single portal venous-phase scanning of the abdominopelvic computed tomography (CT) is, however, reasonably utilized for the evaluation of a clinically palpable mass; the erroneous diagnosis of such aneurysm can be feasible.
Case presentation
A giant idiopathic concealed right iliac artery aneurysm in a 47-day-old girl presented with a palpable pelvic mass regardless of unidentifiable predisposing factors. Non-angiographic abdominopelvic CT was reappraised by the radiology consultant according to discordance between the mass characteristics on initial CT report and those on second-look sonography, revealing the concealed aneurysm instead of solid neoplasm as it originated from right internal iliac artery. The patient underwent an emergency laparotomy with successful proximal ligation of right internal iliac artery despite intraoperative aneurysmal rupture.
Conclusions
Typical CT features for the infantile iliac artery aneurysms may be overlooked, especially if the angiographic phase is omitted; thus, the imaging characteristics of the aneurysms are more difficult to appreciate and can mimic a pelvic neoplasm. Therefore, the identification of the origin of the mass should be more practical to achieve the precise diagnosis.