[Mediastinal mature teratoma perforated into the pericardial sac: a case report]

Mature teratomas occasionally rupture into adjacent organs such as lung, bronchus, mediastinum and pericardial sac. However, perforation into the pericardial sac is rare. We experienced a case of mediastinal mature teratoma perforated into the pericardial sac. A 16-year-old man was admitted to our hospital due to sudden severe anterior chest pain. Chest X-ray showed a mass shadow in the right middle lung field. Chest CT scan and MRI demonstrated a heterogeneous mass with fat component in the right anterior mediastium adjacent to the pericardium. Some squamous cells were obtained from the mass by CT guided percutaneous needle biopsy. Operation was performed with the diagnosis of mediastinal teratoma. The mass adhered to the pericardium and turbid pericardial effusion was noted. The mass was removed with the pericardium. The mass was 9 x 6.5 x 6 cm in size, which contained yellow sebaceous material and a tuft of white hair. The pathological diagnosis of the mass was mature cystic teratoma with perforation into the pericardial sac.