A large ruptured mediastinal cystic teratoma.

A 51-year-old woman presented with a 2-month history of intermittent cough and precordial chest pain associated with shortness of breath. Initial chest-x-ray revealed a large well-circumscribed mass in the left perihilar region and consolidation of left lower lobe. Computed tomography scan of the chest revealed a large irregular fluid-filled mass occupying the left hemithorax, causing a mediastinal shift to the right, and a left pleural effusion. A pigtail was inserted; pleural fluid was exudative without evidence of malignant cells. Left thoracotomy revealed an anterior mediastinal mass of 20 cm in diameter adherent to the pericardium, pleura, and lung. Pathologic examination showed a variety of cell lines consisting of respiratory mucosa, mucous glands, cartilage, smooth muscle, adipose tissue, and pancreatic tissue, results consistent with a mature teratoma. Mature cystic teratomas are usually benign in nature and represent 60% to 70% of mediastinal germ cell tumors; they are found most commonly in young adults. The anterior mediastinum is the most common site for these types of tumors. Rupture of a mediastinal cystic teratoma is a rare event and can be a life-threatening condition. The treatment is mainly surgical, with an excellent prognosis such as in our patient.