A RARE CASE OF MYOCARDIAL INFARCTION DUE TO INTIMAL SARCOMA OF THE AORTIC ARCH

Abstract

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Intimial sarcoma (IS) of the large systemic arteries are an extremely rare class of tumors with only 81 reported cases in literature, most commonly arising in the abdominal aorta (1). Due to its nonspecific clinical presentation, IS is frequently diagnosed late in the disease process when metastasis has already developed, specifically to the lungs, abdominal organs, vertebral bone, and skin (2). Accurate diagnosis is made with immunohistochemical (IHC) staining positive for CD31, Fli-1, and ERG1. We present a case of an IS of the aortic arch resulting in a fatal tumor embolism to the left coronary artery (LCA), as diagnosed on autopsy. CASE PRESENTATION: A healthy 51-year-old male presented with severe sharp pain in the thoracic spine. Physical exam was positive for tenderness to palpation in the mid-thoracic spine with bilateral lower extremity (LE) neurological deficits. Magnetic resonance imaging (MRI) of the spine revealed bone lytic lesions in the thoracic spine from T5 to T7 with a T6 compression fracture. A computed tomography (CT) scan of the chest, abdomen, and pelvis showed no evidence of the primary tumor site. Biopsy revealed metastatic bone sarcoma of unknown origin. The patient underwent palliative radiation therapy for two weeks. One month after completion of treatment, the patient was re-admitted with worsening back pain. Repeat CT scan showed worsening compression fractures and extraosseous tumor extension into the prevertebral space. Subsequently, the patient underwent spinal cord decompression surgery. On post-operative day 4, he developed severe chest pain with refractory ventricular fibrillation leading to his death. Autopsy revealed an IS extending from the aortic arch to the aortic valve with metastasis to the thoracic vertebrae and thyroid gland. Ultimately, the cause of death was due to a tumor embolus that occluded his LCA. DISCUSSION: Aortic IS is an extremely rare neoplasm that typically presents late in the disease process. The initial manifestation of aortic IS in our case was metastatic vertebral bone lesions with no other evidence of the primary site on radiologic modalities, despite retrospective imaging analysis. It is important that aortic IS be included on the differential diagnosis for sarcoma of unknown origin in order to better understand the disease course. To our knowledge, this is the first reported case of aortic IS that presented as a sarcoma of unknown origin with bone metastases and resulted in a myocardial infarction with findings of metastasis to the thyroid gland. CONCLUSIONS: Aortic IS can be classified as: Angiosarcoma, expressing endothelial-specific antigens, and Myofibroblast, expressing mesenchymal-specific antigens. Diagnosis is tricky as IS are easily missed on CT and MRI. Definitive diagnosis requires IHC analysis. Prognosis for aortic IS is quite poor, with a mean survival period of one year. REFERENCE #1: Sebenik, M., et al. (2005). Undifferentiated Intimal Sarcoma of Large Systemic Blood Vessels. American Journal of Surgical Pathology, 29(9), 1184-1193. REFERENCE #2: Staats, P., et al. (2014). Intimal sarcomas of the aorta and iliofemoral arteries: A clinicopathological study of 26 cases. Pathology,46(7), 596-603 DISCLOSURES: No relevant relationships by Daniel Rushing, source=Web Response No relevant relationships by Amjed Zidan, source=Web Response