title: Hyalinizing trabecular tumor of the thyroid: diagnosis of a rare tumor using ultrasonography, cytology, and intraoperative frozen sections.
abstract: OBJECTIVE
  The goal of this study was to evaluate the clinicopathological and imaging features of thyroid nodules surgically diagnosed as hyaline trabecular tumor (HTT), and to assess the role of cytology and frozen sections (FS) in the diagnosis of HTT.
  
  
  METHODS
  This study included 21 thyroid nodules in 21 patients treated from August 2005 to March 2015 (mean age, 53.3 years) who were either diagnosed as HTT or had HTT suggested as a possible diagnosis based on cytology, FS, or the final pathology report. Patients' medical records were retrospectively reviewed for cytopathologic results and outcomes during the course of follow-up. Sonograms were reviewed and categorized.
  
  
  RESULTS
  Twelve nodules from 12 patients were surgically confirmed as HTT. Ultrasonography (US)-guided fine needle aspiration (FNA) was performed on 11 nodules, of which six (54.5%) were papillary thyroid carcinoma (PTC) or suspicious for PTC and three (27.3%) were HTT or suspicious for HTT. Intraoperative FS suggested the possibility of HTT in seven nodules, of which four (57.1%) were confirmed as HTT. US-FNA suggested the diagnosis of HTT in 10 nodules, of which three (30.0%) were confirmed as HTT. Common US features of the 12 pathologically confirmed cases of HTT were hypoechogenicity or marked hypoechogenicity (83.4%), absence of calcifications (91.7%), parallel shape (100.0%), presence of vascularity (75.0%), and probable benignity (58.3%).
  
  
  CONCLUSIONS
  HTT should be included in the differential diagnosis of solid tumors with hypoechogenicity or marked hypoechogenicity and otherwise benign US features that have been diagnosed as PTC through cytology.
authors.affiliation: Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Hyunsik
authors.identifier: 0000-0002-2495-2140
authors.initials: H
authors.lastname: Jang
authors.affiliation: Department of Pathology, Gangnam Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Cheol Keun
authors.identifier: 0000-0001-7689-0386
authors.initials: CK
authors.lastname: Park
authors.affiliation: Department of Radiology, Gangnam Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Eun Ju
authors.identifier: 0000-0002-7895-0335
authors.initials: EJ
authors.lastname: Son
authors.affiliation: Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Eun-Kyung
authors.identifier: 0000-0002-3368-5013
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Jin Young
authors.identifier: 0000-0002-6212-1495
authors.initials: JY
authors.lastname: Kwak
authors.affiliation: Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Hee Jung
authors.identifier: 0000-0002-5643-5885
authors.initials: HJ
authors.lastname: Moon
authors.affiliation: Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Yonsei University, College of Medicine, Seoul, Korea.
authors.forename: Jung Hyun
authors.identifier: 0000-0002-2100-3513
authors.initials: JH
authors.lastname: Yoon
keywords: Biopsy, fine-needle; Frozen sections; Thyroid gland; Thyroid nodule; Ultrasonography