title: Focal myasthenia gravis as a paraneoplastic syndrome of canine thymoma: improvement following thymectomy.
abstract: A 10-year-old, neutered male cocker spaniel-cross experienced regurgitation, dry retching, and weight loss. A large, mediastinal mass and dilatation of the esophagus were seen on thoracic radiographs. Cytological, histopathological, immunohistochemical, and serological findings were consistent with a lymphoepithelial thymoma and focal, esophageal myasthenia gravis. Surgical removal of the mass resulted in rapid resolution of the megaesophagus and a decrease in serum acetylcholine-receptor antibody concentration. The dog was clinically normal until the thymoma recurred six months postoperatively. Clinical signs, diagnostic evaluation, management, and treatment of a dog with thymoma and megaesophagus are described.
authors.affiliation: Department of Veterinary Internal Medicine, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
authors.forename: M F
authors.initials: MF
authors.lastname: Lainesse
authors.forename: S M
authors.initials: SM
authors.lastname: Taylor
authors.forename: S L
authors.initials: SL
authors.lastname: Myers
authors.forename: D
authors.initials: D
authors.lastname: Haines
authors.forename: J D
authors.initials: JD
authors.lastname: Fowler
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000473:pathology* / Q000601:surgery; D004285:Dogs; D004931:Esophageal Achalasia / Q000209:etiology / Q000662:veterinary*; D008297:Male; D008479:Mediastinal Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D009157:Myasthenia Gravis / Q000209:etiology / Q000662:veterinary*; D009364:Neoplasm Recurrence, Local / Q000662:veterinary; D013934:Thymectomy / Q000662:veterinary; D013945:Thymoma / Q000150:complications / Q000473:pathology / Q000601:surgery / Q000662:veterinary*