Posterior Mediastinal Thymoma

Shortness of breath and cough were the sole complaints of a 49-year-old man who had no significant medical history. He was given antibiotics for a possible bronchitis. The patient returned a week later because his symptoms had not improved. At this time, a chest film showed a right-sided mediastinal mass, and a CT scan of the thorax located the mass in the posterior mediastinum. A CT-guided biopsy of the mass showed it to be a stage III invasive thymoma. Dr Chris Derk of Bala-Cynwyd, Pa, reports that the patient was treated successfully with combination chemotherapy (cisplatin, doxorubicin, and etoposide), subsequent surgical excision of the mass, and postoperative radiation therapy.

Posterior mediastinal tumors consist of (in declining order of incidence) neurogenic and mesenchymal tumors; lymphomas; and thyroid, pericardial, and gastroenteric cysts. Thymomas, however, are the most common cause of anterior mediastinal masses. Of these tumors, 70% are benign and 30% are locally invasive. Both benign and malignant types are associated with paraneoplastic syndromes, which include myasthenia gravis, pure red cell aplasia, ectopic Cushing's syndrome, acquired hypogammaglobulinemia, polymyositis, dermatomyositis, systemic lupus erythematosus, and hypertrophic osteoarthropathy.