CIC-rearranged sarcoma presenting with superior vena cava syndrome: case report.

CIC-rearranged sarcomas are rare mesenchymal neoplasms belonging to the family of undifferentiated small round cell sarcomas. This report details the case of a 45-year-old man presenting with symptoms of mediastinal compression, radiological diagnosis of a mediastinal mass and rapid evolution to full-blown superior vena cava syndrome. The emergency was successfully managed with a pharmacological approach. Formulation of a pathological diagnosis of CIC-rearranged sarcoma was initially supported by fluorescence in situ hybridisation findings and later validated by next-generation sequencing, which showed CIC-DUX4 gene fusion. A chemotherapy regimen was started with immediate benefits for the patient. The spectrum of pathological entities able to cause superior vena cava syndrome is wide, and recognition of rare causes is important to tailor the therapeutic approach to the specific disease. This is, to the best of our knowledge, the first report of CIC-rearranged sarcoma presenting with superior vena cava syndrome.