title: Encapsulated anaplastic thyroid carcinoma transformed from follicular carcinoma: a case report.
abstract: BACKGROUND
  Anaplastic thyroid carcinoma (ATC) is rare but is one of the most aggressive and lethal human malignancies. Cytologically, ATC has a variable morphologic appearance, including squamoid, giant, spindled and pleomorphic cells. The coexistence of ATC and differentiated or poorly differentiated thyroid carcinoma has been described and usually is diagnosed when the disease is locally advanced.
  
  
  METHODS
  We describe a case of surgically resectable, encapsulated, well-circumscribed ATC occurring in association with a better differentiated follicular carcinoma diagnosed by fine needle aspiration in a patient exposed to external ionizing radiation.
  
  
  CONCLUSIONS
  Encapsulated variants of anaplastic carcinoma can be seen in association with lower grade thyroid carcinoma such as follicular carcinoma. Accurate diagnosis is dependent on adequate sampling.
authors.affiliation: Department of Pathology, New York University-Bellevue Hospital, 462 First Avenue, Room 4S17A, New York, New York 10016, USA. rapkia01@med.nyu.edu
authors.forename: Amy
authors.initials: A
authors.lastname: Rapkiewicz
authors.forename: Daniel
authors.initials: D
authors.lastname: Roses
authors.forename: Alec
authors.initials: A
authors.lastname: Goldenberg
authors.forename: Pascale
authors.initials: P
authors.lastname: Levine
authors.forename: Michael
authors.initials: M
authors.lastname: Bannan
authors.forename: Aylin
authors.initials: A
authors.lastname: Simsir
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000737:chemistry / Q000556:secondary* / Q000601:surgery; D002471:Cell Transformation, Neoplastic / Q000473:pathology / Q000528:radiation effects; D047852:Chernobyl Nuclear Accident; D006801:Humans; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D016609:Neoplasms, Second Primary; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D014408:Biomarkers, Tumor