title: The ultrasonography features of hyalinizing trabecular tumor of the thyroid gland and the role of fine needle aspiration cytology and core needle biopsy in its diagnosis.
abstract: BACKGROUND
  Hyalinizing trabecular tumor (HTT) of the thyroid gland is a rare, benign neoplasm of follicular cell origin. Misdiagnosis of HTT as either papillary or medullary thyroid carcinoma after fine-needle aspiration (FNA) may lead to unnecessary surgery.
  
  
  OBJECTIVE
  To evaluate the ultrasonography (US) findings of HTT of the thyroid gland and the role of FNA cytology and core needle biopsy (CNB) in its diagnosis.
  
  
  METHODS
  Data from 24 patients with a histopathological diagnosis of HTT between January 2000 and May 2013 were retrospectively analyzed. US findings were categorized according to shape, margin, orientation, echogenicity, composition, calcification, and vascularity. Cytologic and histologic results of FNA, CNB, and surgery were reviewed.
  
  
  RESULTS
  US revealed the following tumor features: oval-to-round (24/24), solid (22/24), smooth margin (21/24), hypoechoic or marked hypoechogenicity (18/24), and peri- and/or intranodular vascularity (17/17). Malignant US features such as marked hypoechogenicity (n = 7) and a spiculated margin (n = 3) were also observed. Final confirmation was by surgery in 22 patients and by CNB in two patients. All 19 patients who underwent FNA were initially misdiagnosed, including 12 with malignancies and five with atypia of undetermined significance. All four patients who underwent CNB were correctly diagnosed with HTT. The histology of CNB specimens suggested HTT, which was confirmed by immunostaining of MIB-1.
  
  
  CONCLUSIONS
  HTT should be suspected when the cytological diagnosis of papillary thyroid carcinoma is made after FNA without malignant US findings. CNB could prevent unnecessary surgery for HTT.
authors.affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Woo Jung
authors.initials: WJ
authors.lastname: Choi
authors.affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea radbaek@naver.com.
authors.forename: Jung Hwan
authors.initials: JH
authors.lastname: Baek
authors.affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea Department of Radiology, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Ha
authors.affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Min Ji
authors.initials: MJ
authors.lastname: Hong
authors.affiliation: Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Dong Eun
authors.initials: DE
authors.lastname: Song
authors.affiliation: Department of Radiology, Thyroid Center, Daerim St. Mary's Hospital, Seoul, Republic of Korea.
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Sung
authors.affiliation: Department of Pathology, Thyroid Center, Daerim St. Mary's Hospital, Seoul, Republic of Korea.
authors.forename: Hyunju
authors.initials: H
authors.lastname: Yoo
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: So Lyung
authors.initials: SL
authors.lastname: Jung
authors.affiliation: Department of Radiology, Inha University Hospital, Incheon, Republic of Korea.
authors.forename: Ha Young
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Jeong Hyun
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000328:Adult; D001707:Biopsy, Needle / Q000379:methods*; D002291:Carcinoma, Papillary / Q000473:pathology; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014463:Ultrasonography
keywords: Hyalinizing trabecular tumor; core-needle biopsy; fine-needle aspiration; thyroid; ultrasonography