[A case of mediastinal myelolipoma].

Myelolipoma is a benign tumor composed of mature adipose tissue and hematopoietic tissue. It was mainly found in the adrenal grand, but there have been reports of extra-adrenal locations. Only 7 cases of mediastinal myelolipoma have been reported ever. We have experienced a case of mediastinal myelolipoma surgically resected from a 55-year-old-man. He has visited our department because of chest pain. Chest X-ray showed typical pneumothorax, but abnormal mediastinal shadow was remarked. Chest CT showed a well circumscribed mass with fat and soft-tissue attenuation in posterior mediastinum. Lung bullectomy and mediastinal tumor resection under VATS was performed. A blue-red tumor 4 cm in diameter was resected en bloc. Pathological examination showed its composition of mature adipose tissue and hematopoietic tissue. Diagnosis was extra-adrenal myelolipoma. No recurrent nor abnormality was found in 8 months since surgery.