title: Fine needle aspiration cytology of the papillary thyroid carcinoma with a solid component: A cytological and clinical correlation.
abstract: BACKGROUND
  Solid variant of papillary thyroid carcinoma is a rare subtype of papillary thyroid carcinoma (PTC) containing a solid component (SC), and thus its cytological and clinicopathological features remain elusive. We examined fine needle aspiration (FNA) cytological features of PTC with variable degrees of SC (20-80% of the tumor)(PTCSC) in comparison to well-differentiated PTC (WPTC).
  
  
  METHODS
  Twenty-six cases of PTCSC were histologically stratified into major-SC (SC >50% of the tumor) and minor-SC (<49%) groups. Pre-operative FNA smears were compared between major-SC (n = 11) and minor-SC (n = 15) groups, and between PTCSC and WPTC (n = 39) groups.
  
  
  RESULTS
  In FNA smears of PTCSC, the presence of cohesive solid nests, trabecular patterns, overlapping, enlarged nuclei, pleomorphism, and distinct nucleolus, and the absence of colloid and psammoma bodies were noted more often than in WPTC, while classical cytological features of PTC, such as nuclear grooves and/or pseudo-nuclear inclusions, were preserved. There was no significant difference in FNA findings between the major-SC and minor-SC groups. The presence of either solid nests or trabecular patterns, and overlapping in FNA smears of PTCSC was associated with a higher recurrence rate of the tumor (P = 0.007 and P < 0.001, respectively).
  
  
  CONCLUSIONS
  PTCSC may pre-operatively be identified by detecting its characteristic cytological features in FNA smears, regardless of the proportion of SC within the tumor. Because clinical outcomes of PTCSC remain undetermined, it is imperative to postulate PTCSC as a differential diagnosis, even when classical nuclear features of PTC are present. Diagn. Cytopathol. 2017;45:391-398. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Ryuji
authors.identifier: http://orcid.org/0000-0001-7053-038X
authors.initials: R
authors.lastname: Ohashi
authors.affiliation: Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Murase
authors.affiliation: Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Matsubara
authors.affiliation: Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Watarai
authors.affiliation: Department of Endocrine Surgery, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Igarashi
authors.affiliation: Department of Endocrine Surgery, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Iwao
authors.initials: I
authors.lastname: Sugitani
authors.affiliation: Department of Diagnostic Pathology, Nippon Medical School Hospital, Tokyo, Japan.|Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo, Japan.
authors.forename: Zenya
authors.initials: Z
authors.lastname: Naito
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000175:diagnosis* / Q000473:pathology; D002291:Carcinoma, Papillary; D003937:Diagnosis, Differential; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000473:pathology; D009367:Neoplasm Staging; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology
keywords: fine needle aspiration; papillary thyroid carcinoma; solid variant