Primary malignant aortic tumors present very rarely. They are usually located at the descending thoracic aorta [1]. The male/female ratio is 9:5 and the mean age of the reported cases is 59.5 years [1]. There are two types of aortic sarcoma; intimal and mural [2]. The intimal type often forms intraluminal polyps or extends along the lumen, causing peripheral emboli or aortic obstruction. The mural type originates from the media or adventitia and usually extends extramurally to paraaortic tissues and lymph nodes [2–4].
Diagnosis of primary aortic tumors is difficult because of the rarity and diverse clinical manifestation of the disease [5]. Aortic sarcomas usually present with clinical signs related to embolization or nonspecific symptoms such as weight loss, fever and anorexia [6]. When the common iliac arteries are involved, the symptoms can be those of ischemia of the lower extremities or decreased peripheral pulses. If the renal arteries are involved, severe hypertension may occur. Gastrointestinal ischemia can be a result of celiac, superior or inferior mesenteric arteries involvement. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are both useful in the differential diagnosis, with some authors advocating the superiority of MRI in detecting arterial wall sarcomas [6]. Histologic examination of the specimen is mandatory and confirms the diagnosis, with intraoperative frozen section analysis assuring adequate resection within clear margins [7].
Our case regards a primary intimal aortic sarcoma, which appears to be only the second one reported in the literature where the diagnosis was completely misled preoperatively and the patient was considered to have thoracoabdominal type IV aortic rupture [8]. In the case reported by Tanaka et al [8] there was indeed an aortic rupture caused by an intimal sarcoma, although the sarcoma was not suspected and was only diagnosed postoperatively, thus limiting the survival of their patient. In contrast, in our case preoperative imaging was misguiding and the suspicion of an underlying tumor was raised intraoperatively, frozen section biopsy was used and a radical excision of the tumor was achieved.
Regarding our patient's preoperative imaging studies, CT revealed an inhomogeneous mildly lobulated mass adjacent to the distal third of the descending aorta, extending caudally up to the level of the superior mesenteric artery. Centrally the contour of the aorta was not distorted, but more distally at the level of the diaphragm there was discontinuity of the aortic wall and the anterolateral margins of the aorta were lost. The lesion showed heterogeneous peripheral and central enhancement. A sufficient fluid collection was also present in the left hemi thorax. Taking into consideration the clinical manifestations, the patient was diagnosed with a contained ruptured aneurysm of the thoracoabdominal aorta. Angiography was also performed and showed moderate narrowing of the contour of the descending thoracic and central abdominal aorta just above the celiac artery, with an ulcer-like projection that was interpreted as a penetrating ulcer.
Prognosis for primary aortic tumors is very poor. The average survival rate is 15.6 months after diagnosis, with the mean survival being 9.8 months for intimal sarcoma [9]. Alexander et al have reported 10 cases in the English literature of primary arterial tumors arising at the anastomotic site of prosthetic woven Dacron graft implantation, though only 7 of them were fully described. The outcome of these cases was relatively poor with 4/7 dying perioperatively and the remaining ones within 10 weeks to 11 months due to metastases or recurrence [10]. They also correlate the presence of the Dacron "foreign body" with the malignant formation. They mention that the mdm-2/p53 pathway has been cited as the possible mechanism for pathogenesis of intimal sarcoma [11, 12]. Thalhmeier showed 20%of tumor cells to be positive for this marker and has implicated a p53 pathway for this malignancy [13].
Primary aortic sarcomas are rarely diagnosed at an early stage due to the diversity of symptoms and the rare incidence of appearance. Since the only potentially curative modality remains radical surgical resection, this treatment option should be offered when the tumor is operable. Chemotherapy should be utilized in embolic, metastatic or nonresectable situations [14]. A combination chemotherapy regimen composed of anthracycline and an alkylating agent may offer a response rate of 20%, however the value of this regimen in the adjuvant setting for intimal aortic sarcoma is unclear [15–17]. Our patient underwent a two-drug chemotherapy treatment (ifosfamide and epirubicin) postoperatively and remains free of recurrence on follow-up MRI and PET scan studies. This could be an indication that radical excision followed by aggressive chemotherapy might be a good treatment option for this rare and highly lethal entity.
