Lipothymoma

Thymolipoma associated with myasthenia gravis

A 51-year-old woman with a 3-year history of diplopia was admitted to our hospital. Repetitive stimulation of the right median nerve revealed decreasing hand muscle responses. Edrophonium chloride administration alleviated the symptoms. The serum antiacetylcholine receptor antibody level was 3.3 nmol/l; thus, myasthenia gravis was diagnosed. A chest roentgenogram revealed a left inferior mediastinal mass, and a chest computed tomographic scan revealed a fat density mass partly containing soft tissue areas in the left side of the anterior mediastinum. Median sternotomy and extended thymectomy were performed. The pathology examination of the tumor revealed mature adipose tissue including islands of thymic tissue containing Hassall's corpuscles, without germinal centers. The tumor was a thymolipoma of the anterior mediastinum. Her postoperative course was good, and she is doing well at 1 year postoperatively.

Thymolipoma

Although the diagnosis of thymolipoma has improved with the introduction of computerized tomography (CT), variations in CT appearance are still being described; this paper describes a case which resembled a lipoma. The CT features of thymolipoma are discussed with special reference to the differential diagnosis. Surgical excision should be considered for patients who are found to exhibit a fatty intrathoracic mass on CT.

Thymolipoma in patients with myasthenia gravis: report of two cases and review

Two cases of simultaneous occurrence of myasthenia gravis (MG) and thymolipoma are described and 4 previously reported cases are reviewed. In all 6 cases, thymectomy was performed. Pre- and postoperatively, the clinical status of the patients was similar to that of late-onset MG without thymolipoma. It is possible that simultaneous occurrence of MG and thymolipoma may be coincidental.