Pericardial Sarcoma: "Invisible" on Radiology.

Primary pericardial tumour is an extremely rare disease and an aggressive carcinoma. Its main presenting symptoms are a large recurrent hemorrhagic pericardial effusion. Imaging is the significant tool in the evaluation of pericardial lesions and of tumours. We report the case of a 17-year-old patient with recurrent hemorrhagic pericardial effusion who was diagnosed with primary pericardial fibrosarcoma. However, multiple radiological examinations, including computed tomography and fludeoxyglucose/positron emission tomography-computed tomography ([18F] FDG/PET-CT) suggested the presence of fluid and no sign of tumour. Actually, when a patient presents with recurrent hemorrhagic pericardial effusions, pericardial tumours must be taken into account as part of the differential diagnosis.