Primary high-grade myxofibrosarcoma in the anterior mediastinum: A case report and review of the literature

Herein, we report on a case of a 70-year-old man with a primary high-grade myxofibrosarcoma (MFS) in the anterior mediastinum. A computed tomography (CT) scan of the patient's chest revealed a heterogeneous mass lesion. On magnetic resonance imaging (MRI), the mass lesion exhibited heterogeneous low signal intensity with focal high signal intensity on T1-weighted images, and high signal intensity with cystic lesions on T2-weighted images. There were no signs of adipose tissue or calcification in the chest CT or MRI findings. Tumor resection was performed for the diagnosis and treatment. The resected mass was composed of myxoid and solid areas. The myxoid areas revealed atypical spindle cells with abundant myxoid matrix. The solid areas showed atypical spindle cell proliferation with numerous mitoses and multinucleated atypical cells. MDM2 gene amplification was not found in the tumor using fluorescent in situ hybridization method. Thus, the tumor was diagnosed as myxofibrosarcoma. Post-operative radiation therapy was administered to the mediastinum. However, the patient died from locally recurrent disease 1-year after surgery. Our case confirms the existence of MFS in the mediastinum and shows its poor prognosis and rapid progression.