Undifferentiated Pleomorphic Sarcoma of the Thoracic Aorta: A Case Report

Abstract

Primary sarcomas of the great vessels are extremely uncommon tumors, with aortic sarcoma being the rarest type. They tend to occur in the thoracic aorta, followed by the abdominal aorta and the thoracoabdominal aorta. They have a propensity for metastases and they cause acute arterial embolism (1).Undifferentiated pleomorphic sarcoma, also called malignant fibrous histiocytoma, has been defined as a group of pleomorphic, high-grade sarcomas that fail to show any line of differentiation using currently available ancillary techniques (2). To the best of our knowledge, no fewer than 24 cases of undifferentiated pleomorphic sarcoma originating from the aorta have been reported in the worldwide literature, but imaging findings have been rarely reported (3-7).Herein, we describe the case of a 67-year-old male who had a primary undifferentiated pleomorphic sarcoma of the descending thoracic aorta with an emphasis on computed tomography (CT) and magnetic resonance imaging (MRI) findings. CASE REPORTA 67-year-old Russian male presented with a 5-month history of epigastric and back pain. The patient had a history of diabetes mellitus and hypertension. Laboratory studies revealed abnormal liver function test (gamma-glutamyl transpeptidase:143 IU/L, alkaline phosphatase: 448 IU/L) and increased C-reactive protein (1.98 mg/dL). Electrocardiogram showed normal sinus rhythm. Contrast enhanced abdomen and chest CT (64-slice multidetector CT, GE Healthcare, LightSpeed VCT, Milwaukee, WI, USA) were performed. Abdomen CT showed no significant findings, and contrast-enhanced CT of the patient's chest showed a heterogeneously enhancing lobulated mass encasing the right aspect of the descending thoracic aorta, extending from the T6 to T8 level, and measuring 1.8 × 3.5 × 3.2 cm in size (Fig. 1A, B). The mass occupied 20% of the aortic lumen, and the intimal layer of the aorta was intact. Thoracic Undifferentiated pleomorphic sarcoma, known as malignant fibrous histiocytoma, arising from the wall of the aorta is an extremely rare tumor. We report computed tomography and magnetic resonance imaging findings of a 67-year-old male patient with histopathologically proven undifferentiated pleomorphic sarcoma arising from the wall of the descending thoracic aorta. To the best of our knowledge, this is the first report of such a case in Korea. Knowledge of imaging findings of undifferentiated pleomorphic sarcoma will be helpful for accurate diagnosis and appropriate management.

Undifferentiated Pleomorphic Sarcoma of the Thoracic Aorta Presenting with Ruptured Saccular Aneurysm: A Case Report

“…그러나 임상 소견과 영상의학적 소견만으로 대동맥의 저혈관성 종양과 죽상경화증 등을 감별하는 것은 쉽지 않다( 7 ). Heo 등( 8 )은 CT에서 대동맥 내막은 정상이며 대동맥 벽의 편심성(eccentric) 비후와 비균질(heterogenous) 조영증강이 관찰되고, MRI에서 T1 강조영상에서 등신호 강도(isosingal intensity)와 강한 주변부 조영증강 및 종괴 내에 비균질 조영증강이 보이며, T2 강조영상에서 고신호 강도를 나타낼 경우 미분화성 다형성 육종을 의심해야 한다고 보고하고 있다. 그러나 본 증례와 같이 대동맥 벽에서 기원하여 소낭성 동맥류를 형성하는 경우는 극히 드물게 증례 보고가 되어 있으며 영상의학적 소견으로 관통성 죽상경화 궤양에 의한 소낭성 동맥류나 진균성 동맥류와 감별이 어려워 술 전 진단이 이루어지지 않는 경우가 대부분이다.…”

“…PET 소견 상 종양의 과대사성 활동(hypermetabolic activity)으로 인해 FDG 섭취가 비후된 대동맥 벽에서 증가하였으며 흉추에도 전이성 병변이 발견되었다. 따라서, CT에서 대동맥에 국소적으로 소낭성 동맥류가 있고 대동맥 벽의 편심성 비후 및 조영증강이 있으면서 다른 대동맥은 정상인 경우, 일차성 대동맥 육종이 원인 질환일 가능성을 반드시 고려하여야 하며 MRI와 PET 등이 대동맥 육종을 진단하는데 도움이 될 수 있다( 4 8 10 )…”

Role of PET/CT in the Evaluation of Aortic Disease

“…3 ). 96 97 98 In patients with peripheral or splanchnic emboli, an aortic sarcoma should be included in differential diagnosis; therefore, a whole-body PET/CT scan can be used for comprehensive staging. 99 In one study of primary sarcomas of the aorta and arteries, 100 FDG PET/CT showed high metabolic activity in sarcomas, local embolic spread in the pulmonary vasculature of the lungs, distant metastases to the brain, and high metabolic activity at the site of vascular filling defects, which strengthens the suspicion of malignant disease.…”