title: Microthymoma in elderly-onset myasthenia gravis detected preoperatively.
abstract: A 77-year-old woman with a 3-month history of muscle weakness was diagnosed with elderly-onset generalized myasthenia gravis (Myasthenia Gravis Foundation of America classification IIa) based on a high serum acetylcholine receptor antibody level (25.4 nmol·L-1) and neurological findings. Computed tomography detected a small nodule (diameter 15 mm) in the anterior mediastinum, which was suspected to be a thymoma. An extended thymectomy was performed. The pathological examination revealed a 6-mm-diameter thymoma, termed a microthymoma, accompanied with a unilocular thymic cyst without capsule formation (type B2 according to the World Health Organization classification). Some fat tissue was also found within the tumor.
authors: Department of Thoracic Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan haruakihino@gmail.com.
authors: Haruaki
authors: H
authors: Hino
authors: Department of Thoracic Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors: Takashi
authors: T
authors: Nishimura
authors: Department of Pathology, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors: Atsuko
authors: A
authors: Seki
authors: Department of Thoracic Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.|Department of Thoracic Surgery, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
authors: Jun-Ichi
authors: JI
authors: Nitadori
authors: Department of Pathology, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.
authors: Tomio
authors: T
authors: Arai
authors: Department of Thoracic Surgery, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan.|Department of Thoracic Surgery, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
authors: Jun
authors: J
authors: Nakajima
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009157:Myasthenia Gravis / Q000150:complications* / Q000175:diagnosis / Q000601:surgery; D013934:Thymectomy; D013945:Thymoma / Q000737:chemistry / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D016606:Thyroid Nodule / Q000737:chemistry / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor
keywords: Aging; Mediastinal cyst; Myasthenia gravis; Thymectomy; Thymoma; Thymus neoplasms