title: Characteristics of ectopic parathyroid glands in 145 cases of primary hyperparathyroidism.
abstract: OBJECTIVE
  To determine the prevalence of primary hyperparathyroidism (PHPT) arising from ectopic parathyroid glands, to analyze the clinical, biochemical, and anatomic characteristics of such cases, and to compare these characteristics with those found in PHPT associated with orthotopic parathyroid glands.
  
  
  METHODS
  We conducted a retrospective study of cases of PHPT evaluated and treated at a referral center. Differences between patients with orthotopic and ectopic parathyroid glands were analyzed statistically.
  
  
  RESULTS
  During a recent 5-year period at our institution, 145 cases of PHPT were treated operatively by 3 experienced surgeons. An ectopic parathyroid location was detected in 13 cases (9%). Of the 13 ectopic glands, 4 (31%) were at the tracheoesophageal groove, 4 (31%) were intrathymic, 2 (15%) were intrathyroidal, and 1 each was located in the aortopulmonary window, the anterior (nonthymic) mediastinum, and the submaxillary region. Patients with PHPT attributable to ectopic adenomas had significantly higher serum calcium levels (12.6 ± 0.9 mg/dL versus 11.4 ± 1.2 mg/dL; P = .05) and larger tumors (25 ± 6.1 mm versus 19 ± 7.6 mm; P = .05) than did patients with orthotopic parathyroid glands. Moreover, hyperparathyroidism- related bone disease was significantly more frequent in patients with abnormal ectopic parathyroid glands than in those with orthotopic parathyroid glands (23% versus 1.5%, respectively; P = .04).
  
  
  CONCLUSIONS
  In 9% of all cases of PHPT in our study, the condition was associated with ectopically located parathyroid glands. Such cases are usually characterized by larger parathyroid glands, higher serum calcium levels, and a higher frequency of severe bone disease.
authors.affiliation: Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México City, México. vmendozazu@yahoo.com
authors.forename: Victoria
authors.initials: V
authors.lastname: Mendoza
authors.forename: Claudia
authors.initials: C
authors.lastname: Ramírez
authors.forename: Amparo E
authors.initials: AE
authors.lastname: Espinoza
authors.forename: Gloria A
authors.initials: GA
authors.lastname: González
authors.forename: Juan F
authors.initials: JF
authors.lastname: Peña
authors.forename: Martha E
authors.initials: ME
authors.lastname: Ramírez
authors.forename: Irma
authors.initials: I
authors.lastname: Hernández
authors.forename: Moisés
authors.initials: M
authors.lastname: Mercado
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies