title: Magnetic resonance imaging features of spontaneously regressed thymoma: report of 2 cases.
abstract: The authors describe 2 cases in which thymoma spontaneously regressed. The first patient was a 49-year-old woman with myasthenia gravis. A chest radiograph on admission showed an anterior mediastinal mass that spontaneously decreased in size as shown on a radiograph obtained 2 weeks later. Surgical removal of the mass was performed and the histopathologic examination showed a type B2 thymoma with marked coagulation necrosis in the central area. The second patient was a 46-year-old woman who was hospitalized due to chest and back pain. A chest radiograph on admission showed an anterior mediastinal mass and bilateral pleural effusion. The mass decreased in size and the effusion disappeared as shown on a chest radiograph obtained 2 months later. Computed tomography-guided biopsy was performed, and histopathologic examination revealed thymoma with marked necrosis. In both cases, dynamic contrast-enhanced magnetic resonance images showed peripheral ringlike enhancement of the mass. The clinical and radiologic features of spontaneously regressed thymoma may be different from those of common thymoma.
authors.affiliation: Department of Radiology, Faculty of Medicine, Saga University, Saga, Japan. nakazot@cc.saga-u.ac.jp
authors.forename: Takahiko
authors.initials: T
authors.lastname: Nakazono
authors.forename: Ken
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Ryoko
authors.initials: R
authors.lastname: Egashira
authors.forename: Toshimi
authors.initials: T
authors.lastname: Satoh
authors.forename: Fumio
authors.initials: F
authors.lastname: Yamasaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mitsuoka
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Hayashi
authors.forename: Sho
authors.initials: S
authors.lastname: Kudo
mesh_terms: D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D012075:Remission, Spontaneous; D013945:Thymoma / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D013953:Thymus Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery
chemical_list: D003287:Contrast Media