title: Benign ectopic thyroid tissue in a cutaneous location: a case report and review.
abstract: BACKGROUND
  For many years, lateral, aberrant thyroid tissue in adults was a term used almost exclusively for metastatic thyroid carcinoma. However, aberrant, benign ectopic thyroid tissue does occur, and it is most commonly found as a part of the evaluation of endocrine dysfunction. Rarely, aberrant, benign ectopic thyroid presents as a primary mass.
  
  
  METHODS
  We present a 35-year-old female who presented for removal of a lifelong posterior lateral neck nodule.
  
  
  RESULTS
  Histologic examination and immunohistochemical studies confirmed the presence of aberrant, benign ectopic thyroid tissue. The patient had no endocrine problems, and she had a normally located and functioning thyroid gland.
  
  
  CONCLUSIONS
  This case illustrates that not all aberrant thyroid tissues in adults are malignant or associated with endocrine disorders. This case also illustrates the rare association of ectopic thyroid and a normally located and functioning thyroid gland. In this patient, a somatic mutation in a transcription factor important in thyroid migration could explain these findings.
authors.affiliation: Department of Dermatology, National Naval Medical Center, Bethesda, MD, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Maino
authors.forename: Henry
authors.initials: H
authors.lastname: Skelton
authors.forename: Josef
authors.initials: J
authors.lastname: Yeager
authors.forename: Kathleen J
authors.initials: KJ
authors.lastname: Smith
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002828:Choristoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D012871:Skin Diseases / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D013961:Thyroid Gland
chemical_list: D015415:Biomarkers