Myasthenia gravis associated with thymolipoma: a case report.

A 31-year-old patient with a 2-year history of myasthenia gravis underwent resection of a mass in the anterior mediastinum. On histological examination, the tumour proved to be a thymolipoma. The association of thymolipoma with myasthenia gravis is rare. To our knowledge this is the 12th case reported. It is however the first in which histological examination revealed the presence of germinal centres. The tumour measured 28 x 14 x 2 cm and weighted 340 gr. This is by far the largest thymolipoma associated with myasthenia gravis reported. As in all previously published cases, the myasthenia associated symptoms improved significantly after surgery. In this case improvement occurred within weeks. In general, benefit after thymectomy is delayed until months to years.