A CASE OF MYASTHENIA GRAVIS ASSOCIATED WITH THYMOMA AND MULTILOCULAR THYMIC CYST IN MULTIPLE ENDOCRINE NEOPLASIA TYPE 1 SYNDROME

Abstract

An about 40-year-old female patient who had been treated for multiple endocrine neoplasia (MEN) type 1 syndrome was referred to us because of difficulties in swallowing and in raising the neck. The patient was diagnosed as having myasthenia gravis with thymoma, and underwent extended thymectomy. Pathological examination revealed that thymoma was classified as type B2 according to WHO classification, and in Stage I according to Masaoka's classification. In addition, a multilocular cyst was demonstrated with clear separation from the thymoma. The histologic features of the cyst were compatible with those reported by Suster and Rosai, who suggested that it arises from processes of reactions to an acquired inflammatory change. Surveillance CT scans of the chest that had been sequentially taken for follow-up of MEN type 1 syndrome in another hospital suggested that the thymoma developed first and occurrence of the thymic cyst was afterward.