Aortic sarcoma mimicking a mycotic aneurysm in the thoracoab
Aortic sarcoma is a rare primary tumor. Although accurate preoperative diagnosis is essential to completely resect the diseased aorta, the rarity of this tumor makes clinical differentiation difficult. We report a case of aortic sarcoma mimicking a saccular mycotic aneurysm on preoperative radiological images and clinical presentation.

A 74-year-old woman with a history of hypertension and hyperlipidemia presented to a hospital with a primary complaint of upper abdominal pain. Upper endoscopy revealed a 3- × 3-cm mass in the gastric greater curvature with ulceration, pathologically defined as necrotic tissue with nonspecific inflammation. Abdominal plain computed tomography (CT) revealed mild thickening of the gastric wall, slight enlargement of the thoracoabdominal aorta, and celiac trunk occlusion. No other remarkable findings were detected. Her symptoms initially resolved spontaneously.

Two months later, she returned to our hospital complaining of persistent upper abdominal pain, general fatigue, and appetite loss. She had low-grade fever and mild tenderness of the upper abdomen. Physical examination was otherwise unremarkable. Laboratory tests revealed elevated white blood cell count and serum C-reactive protein level (16.6 × 104/μL and 21.7 mg/dL, respectively); the procalcitonin level was normal.

Repeat blood cultures taken on admission were negative. Enhanced CT showed a 29-mm saccular thoracoabdominal aortic aneurysm and occlusion of the celiac trunk. No contrast enhancement surrounding the aneurysm wall was found. Upper endoscopy demonstrated a 7- × 4-cm submucosal tumor on the gastric greater curvature, with necrotic ulceration. The gastric sarcoma was diagnosed pathologically. A broad-spectrum antibiotic was administered intravenously for a presumptive diagnosis of mycotic aortic aneurysm, but her fever persisted despite intensive therapy.

Primary malignant aortic sarcoma is extremely rare, with only 140 cases reported.1 In 1873, Brodowski documented the first case of aortic sarcoma. This tumor shows a slight male predominance, and occurs at a mean age of 60 years. The descending thoracic aorta is the most common site, followed by the abdominal aorta and thoracoabdominal aorta.

Thalheimer et al. differentiated aortic sarcomas clinicopathologically into intimal and mural subtypes. Sarcomas of the intimal subtype originate from the intima and express endothelium-specific immunohistochemical markers, such as CD31 and/or factor VIII. It commonly forms a luminal mass, causing arterial obstruction and distal embolization. The mural subtype is less frequent, develops from the media or adventitia, and involves the extra-aortic soft tissues. This subtype rarely interrupts the aortic circulation. It commonly lacks the immunohistochemical expression of endothelial markers. In our case, the primary tumor showed extraluminal growth and no aortic obstruction, clinically similar to the mural subtype.

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