Compression of superior vena cava and azygos vein by a giant mediastinal mature cystic teratoma: a case report

Teratoma is a common type of mediastinal tumor, often located in the anterior mediastinum. Mediastinal teratomas often occur in young and middle-aged people, and account for 5–21.5% of mediastinal tumors. Mature cystic teratoma is a common type of mediastinal teratoma, its onset is slow, and most patients are asymptomatic. In a few patients, the tissue around the mediastinum is invaded or there is malignant transformation, which results in chest pain, chest tightness, a cough, and other symptoms. In this case, the patient had a giant teratoma, compressing large blood vessels and nerves, complicated by pleural and pericardial effusion. The 21-year-old female patient was misdiagnosed with tuberculous disease because of chronic cough and expectoration. Her initial symptoms improved after anti-tuberculosis treatment; however, an imaging examination showed that the lesion had enlarged some 9 months later. Surgery was performed at our hospital, as the tumor was squeezing blood vessels, and the trachea was seriously adhering to the surrounding tissue. To avoid damage to the peripheral blood vessels and nerves, many residual tissues were retained after the operation. The post-operative pathology results confirmed that the patient had a mature mediastinal cystic teratoma. One year after the operation, there was no recurrence, the peripheral blood vessels had basically returned, and the patient did not have any nerve injury. Effusion caused by mediastinal teratoma should be carefully differentiated from tuberculous diseases to avoid unnecessary damage to patients during treatment. Separation can be difficult in benign mediastinal tumors with severe adhesion. To avoid the trauma caused by the excessive separation of a tumor, it is our view that part of the residual tissue should be retained and left to be absorbed naturally.