DICER1-associated sarcoma of the aortic arch - a case report and literature review

Primary sarcoma of the aorta is extremely rare. We herein report a case of DICER1-associated sarcoma originating from the aortic arch. A 45-year-old male was admitted to the hospital with a cold left hand and weakened radial artery pulse in the left side. Computed tomography of the chest showed multiple penetrating ulcers with tumor-like ectasia at the aortic arch, diagnosed as a pseudoaneurysm. Histopathological analysis of the mass revealed a biphasic neoplasm composed of epithelial and mesenchymal components and a transition zone between the epithelial and mesenchymal cells, which supports the diagnosis of a biphasic sarcoma rather than carcinosarcoma. The differentiated cells of soft tissue showed strong and diffuse positivity for TLE-1, Bcl-2, and CD99; the nested epithelial cells were focally positive for CK-pan, but negative for EMA, membranous localization of β-catenin. This case showed a unique pattern of SS18-break-apart probe, with loss of the green signal (approximately 33%) by fluorescence in situ hybridization (FISH). Fusion gene profiling using whole transcriptome RNA sequencing (RNA-seq) indicated that this case was negative for common fusion genes including SS18. Next-generation sequencing (NGS) revealed somatic mutations in DICER1 . Taken together, this case was diagnosed as a DICER-associated biphasic sarcoma of the aortic arch. The patient died four months after aorta replacement therapy without radiotherapy and chemotherapy.

Undifferentiated intimal sarcoma mimicking a mycotic aneurysm

Summary: Intimal sarcoma of arteries is a rare malignant tumor, which often mimics other vascular disorders; therefore, preoperative diagnosis is often challenging. We herein report a 71-year-old man who presented with fever and elevated inflammatory markers who had a mass in the left internal iliac artery with rapid growth. Based on clinical findings, a diagnosis of mycotic aneurysm was made. We performed surgical intervention, including resection of the affected vessels with omentopexy, although intraoperative findings were not typical of a mycotic aneurysm. Microscopic and immunohistochemical examination demonstrated undifferentiated intimal sarcoma. The patient died of multiorgan failure two months after the surgery. The vascular surgeon should consider the possibility of a diagnosis of intimal sarcoma for patients with atypical findings and the importance of histological and immunohistochemical examination for precise diagnosis in surgical vascular cases.