Rebound thymic hyperplasia after chemotherapy in a patient treated for pulmonary metastases.

A 38-year-old patient presented with an anterior mediastinal mass after chemotherapeutic and surgical treatment for lung metastases from a malignant histiocytoma. Because of the risk for tumour recurrence the thymic mass was resected. Thymic hyperplasia was found on pathological examination. In this case thymic hyperplasia is a rebound phenomenon aflcer chemotherapy. It appears to atrophy during the administration of chemotherapy and regrow afterwards. Surgical resection provides the definitive diagnosis and treatment.