title: Ewing sarcoma of the thyroid: report of 2 cases and review of the literature.
abstract: BACKGROUND
  Neuroendocrine tumors of the thyroid encompass a wide differential diagnosis. The most common is medullary thyroid carcinoma. One must consider other possibilities when a neuroendocrine thyroid tumor is calcitonin negative. We report 2 cases of Ewing sarcoma of the thyroid and discuss the differential diagnosis and workup of a calcitonin-negative neuroendocrine tumor of the thyroid.
  
  
  RESULTS
  This is a retrospective review of 2 patients diagnosed with Ewing sarcoma of the thyroid and a review of the literature.
  
  
  CONCLUSIONS
  Ewing sarcoma of the thyroid is an exceedingly rare diagnosis, but should be included in the differential diagnosis for a thyroidal neuroendocrine lesion (especially in the absence of calcitonin). The use and interpretation of immunohistochemistry (IHC) and fluorescent in situ hybridization are essential in making the correct diagnosis.
authors.affiliation: Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Chan
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Bilodeau
authors.forename: Scott
authors.initials: S
authors.lastname: Celin
authors.forename: Yuri
authors.initials: Y
authors.lastname: Nikiforov
authors.forename: Jonas T
authors.initials: JT
authors.lastname: Johnson
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D001707:Biopsy, Needle; D017024:Chemotherapy, Adjuvant; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008297:Male; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000473:pathology*; D035583:Rare Diseases; D012512:Sarcoma, Ewing / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor