title: Columnar cell variant of papillary thyroid carcinoma: Cytomorphological characteristics of 11 cases with histological correlation and literature review.
abstract: BACKGROUND
  The columnar cell variant of papillary thyroid carcinoma (PTC-CCV) is a rare entity that demonstrates a more aggressive clinical course compared with the more common subtypes of PTC. On histology, it is defined by papillae or gland-like structures lined by columnar cells displaying prominent nuclear stratification. Because to the authors' knowledge no characteristic cytomorphological features have been identified to date and typical features of PTC often are absent on cytology, the diagnosis of PTC-CCV by fine-needle aspiration (FNA) is challenging. This prompted the authors to evaluate a series of PTC-CCV cases to identify features that could facilitate its diagnosis by FNA.
  
  
  METHODS
  A total of 11 surgical specimens of PTC-CCV with corresponding preoperative cytology were identified over a 21-year period. The cytological features of the aspirated specimens, consisting mostly of Papanicolaou and Diff-Quick smears, were evaluated retrospectively.
  
  
  RESULTS
  All cases demonstrated the presence of papillary structures. The most important features observed in PTC-CCV FNA specimens were hypercellularity with nuclear superposition and a paucity of nuclear pseudoinclusions and grooves.
  
  
  CONCLUSIONS
  Although PTC-CCV may demonstrate features that overlap with those of the classic variant of PTC, hypercellular smears with papillary structures covered by cells with pseudostratified nuclei that show a paucity of nuclear pseudoinclusions and grooves should alert the cytopathologist to the possibility of this diagnosis. Cancer Cytopathol 2017;125:389-97. © 2017 American Cancer Society.
authors.affiliation: Clinical Pathology Service, Institute of Pathology, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Massimo
authors.identifier: http://orcid.org/0000-0001-9846-6682
authors.initials: M
authors.lastname: Bongiovanni
authors.affiliation: Department of Otolaryngology and Head and Neck Surgery, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Maxime
authors.initials: M
authors.lastname: Mermod
authors.affiliation: Division of Cytology, Department of Pathology, Acibadem University, Istanbul, Turkey.
authors.forename: Sule
authors.initials: S
authors.lastname: Canberk
authors.affiliation: Clinical Pathology Service, Institute of Pathology, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Chiara
authors.initials: C
authors.lastname: Saglietti
authors.affiliation: Endocrinology, Diabetology, and Metabolism Service, Lausanne University Hospital, Lausanne, Switzerland.
authors.forename: Gerasimos P
authors.initials: GP
authors.lastname: Sykiotis
authors.affiliation: Department of Clinical Pathology, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Pusztaszeri
authors.affiliation: Pathology Unit, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Moira
authors.initials: M
authors.lastname: Ragazzi
authors.affiliation: Institute of Pathology, Locarno, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Mazzucchelli
authors.affiliation: Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
authors.affiliation: Pathology Unit, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Piana
mesh_terms: D000328:Adult; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000473:pathology*; D002291:Carcinoma, Papillary; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology*; D047368:Tumor Burden
keywords: columnar cell variant; differential diagnosis; fine-needle aspiration (FNA); papillary thyroid carcinoma (PTC); thyroid cancer