[Thymolipoma in association with myasthenia gravis; report of a case].

An 18-year-old man was admitted with easy fatigue and muscle weakness. A diagnosis of myasthenia gravis was made. Chest X-ray showed no mediastinal abnormality, however, chest computed tomography (CT) showed a soft tissue mass in the thymus. The patient underwent extended thymectomy and small tumor (2 x 2 x 2 cm) was resected. On histological examination the tumor proved to be a thymolipoma composed of mature adipose elements containing cords and nests of thymic tissue. Symptoms of myasthenia gravis were dramatically improved after the operation. This case is the 12th in the world literature in which a thymolipoma is associated with symptoms of myasthenia gravis.