Undifferentiated Intimal Sarcoma of the Large Abdominal Arteries Presenting As Acute Mesenteric Ischemia: A Case Report

Primary malignant tumors of the large arteries are exceedingly rare and diagnostically challenging. Undifferentiated intimal sarcomas and leiomyosarcomas are the major types encountered. Intimal sarcomas are highly aggressive neoplasms characterized by intraluminal growth and a tendency to mimic thromboembolic disease, often resulting in delayed diagnosis and poor outcomes. We report the case of a 63-year-old man who presented with progressive abdominal pain and weight loss and rapidly developed acute mesenteric ischemia due to extensive intraluminal obstruction of the descending and abdominal aorta with involvement of major visceral branches. Despite emergency surgical interventions, including thrombectomy, vascular bypass, and four re-laparotomies, the clinical course was marked by rapid re-thrombosis, sepsis, and multiorgan failure. Histopathological examination of retrieved intravascular material revealed a high-grade undifferentiated sarcoma that was confirmed at autopsy as an undifferentiated intimal sarcoma of the large arteries. This case highlights the diagnostic pitfalls of malignant vascular tumors and underscores the importance of considering intimal sarcoma in patients with atypical or recurrent arterial thrombosis, particularly when multiple visceral vessels are involved.