title: Fine needle aspiration cytology of parathyroid lesions.
abstract: BACKGROUND
  There has been an increase in the use of fine needle aspiration cytology (FNAC) for the diagnosis of parathyroid lesions (PLs). Differentiation between a thyroid lesion and a PL is not easy because of their similar features. We reviewed parathyroid aspirates in our institution and aimed to uncover trends in diagnostic criteria.
  
  
  METHODS
  We selected 25 parathyroid aspirates (from 6 men and 19 women) confirmed surgically or immunohistochemically from 2006 to 2011.
  
  
  RESULTS
  Major architectural findings of PLs include scattered naked nuclei, loose clusters, a papillary pattern with a fibrovascular core, tight clusters, and a follicular pattern. These architectures were commonly admixed with one another. Cytological features included anisokaryosis, stippled chromatin, a well-defined cell border, and oxyphilic cytoplasm. Eighteen of the 25 patients were diagnosed with PL using FNAC. Seven patients had been misdiagnosed with atypical cells (n=2), benign follicular cells (n=2), adenomatous goiter (n=2) and metastatic carcinoma (n=1) in FNAC. Using clinicoradiologic data, the sensitivity of the cytological diagnosis was 86.7%. The cytological sensitivity decreased to 50% without this information.
  
  
  CONCLUSIONS
  FNAC of PL is easily confused with thyroid lesions. A combination of cytological parameters and clinical data will be required to improve the diagnostic sensitivity of PLs.
authors.affiliation: Department of Pathology, Korea Cancer Center Hospital, Seoul, Korea.
authors.forename: Ilyeong
authors.initials: I
authors.lastname: Heo
authors.forename: Sunhoo
authors.initials: S
authors.lastname: Park
authors.forename: Chang Won
authors.initials: CW
authors.lastname: Jung
authors.forename: Jae Soo
authors.initials: JS
authors.lastname: Koh
authors.forename: Seung-Sook
authors.initials: SS
authors.lastname: Lee
authors.forename: Hyesil
authors.initials: H
authors.lastname: Seol
authors.forename: Hee Seung
authors.initials: HS
authors.lastname: Choi
authors.forename: Soo Youn
authors.initials: SY
authors.lastname: Cho
keywords: Biopsy, fine-needle; Cytology; Parathyroid lesions