Aortic fibrosarcoma presenting as rupture of an abdominal aortic aneurysm

Abstract

A 48-year-old man was admitted to our emergency department with a sudden onset of severe abdominal pain. He reported a 2-week history of back pain, with complaints of amass on his left thigh, andwas amidst further evaluation by a local physician.On arrival, he was tachycardic with profound diaphoresis. Abdominal examination revealed tenderness elicited on palpitation and a large pulsatingmass in his left upper quadrant.His initial laboratory resultswereunremarkableother thana slight increase inwhitebloodcell count. Computed tomography imaging revealed an intraperitoneal hematoma and an extensively dilated infrarenal abdominal aorta with a maximal diameter of 84 mm (Cover). The aneurysmal wall was irregular but well defined and appeared to contain intramural thrombus that showed subtle late-phase enhancement (A). An urgent midline laparotomy was performed. The surface of the aneurysm was irregular but covered by retroperitoneal membrane. It showed little adhesion to the omentum and no adhesion to the intestines (B). The abdominal aortawas clampedproximally anddistally to the aneurysm, and the aneurysm was opened. Atherosclerotic findings inside were minimal, but therewas a defect of the intimal layer of the anteriorwall.The aneurysmwas resected, and the abdominal aorta was reconstructed with a woven polyester tube graft. Histopathologic analysis revealed massive proliferation of fibroblastic tumor cells invading the entire layer of the aorta anddestroying the intima. The adventitia remained patent, suggesting that the tumor originated from the aorta and was not a metastatic entity from adjacent organs. Furthermore, the tumor cells formed fascicles with vague herringbone pattern (C), consistently stained positive for vimentin, and showed Ki-67 labeling index of 50%. Taken together, these findings suggested that a high-grade adult fibrosarcoma (World Health Organization classification) arising from the aortic wall led to a ruptured pseudoaneurysm. Postoperativemagnetic resonance imaging revealedmultiplemetastasis to the vertebral bodies and adductor muscles, and the patient was promptly introduced to ifosfamide-based chemotherapy combinedwith radiotherapy. Primary aortic sarcomas are extremely rare, but may cause aortic rupture, dissection, or ischemia, and attention is required when diagnosing and treating aortic emergencies. Written consent was obtained from the patient for publication of the study.