title: The frequency of ectopic thymic tissue in the necks of patients without any thymic disease.
abstract: BACKGROUND
  Incidences of ectopic thymic tissue in the neck have been reported in various conditions. Despite their diversity, there are only a few studies focusing on patients without any thymic disease. The goal of this study was to detect the frequency of ectopic thymic tissue in the necks of adult patients without any thymic disease.
  
  
  METHODS
  Ninety patients with thyroid disorder who were candidate for thyroidectomy were selected. Five specimens were taken from each patient, including two biopsies before thyroidectomy from the right and left thyrothymic ligament just near the thyroid. The other specimens were taken after thyroidectomy: two from right and left carotid sheet at the base of the neck and the fifth from the adipose tissue just above the fourth tracheal cartilage. The specimens were stained with H&E and cytokeratin antibody to detect thymic tissue.
  
  
  RESULTS
  Ectopic thymic tissue was found in four cases (4.45%), one by H&E and the others by immunohistochemical staining.
  
  
  CONCLUSIONS
  In patients with myasthenia gravis, hyperplasia of thymic tissue occurs in their thymus gland and ectopic thymic tissue as well. As a result, the probability of finding ectopic thymic tissue in such a patient is higher than in patients without any thymic disease. Also, removing of this tissue can improve the outcome of patients.
authors.affiliation: Department of Thoracic Surgery, Isfahan University of Medical Sciences, School of Medicine, Iran.
authors.forename: Seid Abbas
authors.initials: SA
authors.lastname: Tabatabaie
authors.forename: Seid Mozafar
authors.initials: SM
authors.lastname: Hashemi
authors.forename: Behnam
authors.initials: B
authors.lastname: Sanei
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Sanei
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D002828:Choristoma / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000473:pathology*; D013950:Thymus Gland / Q000473:pathology*