title: Micropapillary thyroid carcinoma and concomitant ectopic thyroid tissue in the adrenal gland: metastasis or metaplasia?
abstract: BACKGROUND
  Ectopic thyroid tissue is a rare finding but has been reported in many thoracic and abdominal locations. It is usually an incidental pathologic finding after an unrelated surgical intervention. When thyroid tissue is found outside the thyroid bed, it is important to rule out thyroid cancer metastasis.
  
  
  METHODS
  We present a case of a 61-year-old African American woman who was incidentally found to have concomitant ectopic thyroid tissue in the adrenal gland and a papillary thyroid microcarcinoma (PTMC) in the right lobe of the thyroid.
  
  
  CONCLUSIONS
  The concurrent finding of ectopic thyroid tissue and PTMC posed the diagnostic dilemma of whether the extrathyroidal tissue was metastasis or metaplasia, with very different treatment implications. Although many of these incidental micropapillary cancers are indolent, some patients do experience local or distant metastasis. Therefore, it is important to delineate which of these microtumors are likely to metastasize. Some tumor markers and gene mutations have been proposed to help differentiate the more benign tumors from the more aggressive tumors, but there is currently no standard method for determination of metastatic potential.
  
  
  CONCLUSIONS
  Here we present the seventh known case of ectopic thyroid tissue in the adrenal gland and the first case of concomitant incidental PTMC in the setting of this ectopic tissue finding. Using this case, we discuss the diagnostic and therapeutic challenges faced and propose the use of biomarkers to help determine the metastatic potential of these tumors.
authors.affiliation: Division of Diabetes, Endocrinology, and Metabolism, Duke University Hospital, Durham, NC 27710, USA. brittany.bohinc@duke.edu
authors.forename: Brittany N
authors.initials: BN
authors.lastname: Bohinc
authors.forename: John C
authors.initials: JC
authors.lastname: Parker
authors.forename: William W
authors.initials: WW
authors.lastname: Hope
authors.forename: Cyrus
authors.initials: C
authors.lastname: Kotwall
authors.forename: John
authors.initials: J
authors.lastname: Turner
authors.forename: Wanli
authors.initials: W
authors.lastname: Cheng
authors.forename: Ricardo V
authors.initials: RV
authors.lastname: Lloyd
mesh_terms: D000307:Adrenal Gland Diseases / Q000150:complications / Q000175:diagnosis*; D000310:Adrenal Gland Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000556:secondary; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D002277:Carcinoma; D002291:Carcinoma, Papillary; D002828:Choristoma; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D033162:Incidental Findings; D008679:Metaplasia; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011237:Predictive Value of Tests; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy / Q000556:secondary; D013974:Thyroxine / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D013974:Thyroxine