Thyroid gland
Papillary carcinoma
Cytology

Author: Shahidul Islam, M.D., Ph.D. (see Authors page)

Revised: 19 July 2018, last major update March 2009

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: papillary thyroid carcinoma cytology
Cite this page: Islam, S. Cytology. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/thyroidpapillarycytology.html. Accessed October 22nd, 2018.
Definition / general
  • Suggestive of papillary thyroid carcinoma:
    • Extensive nuclear inclusions or nuclear grooves, papillary formations, no colloid (Arch Surg 2006;141:961)
    • If only < 20 cells with features of papillary carcinoma, is associated with a high rate of papillary carcinoma at resection, usually classic type and > 1 cm (Am J Clin Pathol 2002;118:208)
  • Indeterminate for papillary thyroid carcinoma:
  • Probably not papillary thyroid carcinoma:
    • Rare intranuclear inclusions or nuclear grooves alone in an otherwise benign specimen
  • Addition of BRAF analysis may be useful (Endocr J 2007;54:399)
  • False negatives usually due to nodule heterogeneity (Cancer 2008;114:27)
Cytology description
  • Cellular aspirate with monolayer sheets of cells, often with 3 dimensional papillary architecture (thick or thin fragments with fibrovascular cores), multilayered syncytial fragments or branched sheets
  • Often psammoma bodies
  • Cellular swirls in 17% (relatively specific, Mod Pathol 2006;19:1470)
  • Cells have dense squamoid cytoplasm, enlarged overlapping nuclei with irregular contours, intranuclear inclusions and grooves (don't see ground glass nuclei), pale finely granular chromatin and multiple micronucleoli
  • Also have multinucleated giant cells, metaplastic squamous cells and gummy colloid
  • Rarely atypical histiocytes (Diagn Cytopathol 2009;37:244)
  • Note: no feature by itself is diagnostic, must see a constellation of findings; specific findings for variants are described below
Cytology images

Images hosted on PathOut server:

Contributed by Andrey Bychkov, M.D., Ph.D.

Pink intranuclear
cytoplasmic inclusion vs.
intranuclear bubbles

Microfollicle, enlarged
nuclei and single
intranuclear inclusion


Contributed by Mark R. Wick, M.D.

Classical type



Images hosted on other servers:

Papillary architecture

Sheets of cells with sparse colloid

Classic nuclear features


Focal nuclear crowding and nuclear grooves

Intranuclear inclusions

Ground glass nuclei

Nuclear size variation,
microfollicular pattern
and intranuclear
pseudoinclusion


Psammoma bodies

Cell block

Metaplastic squamous cells

Cystic tumor (fig 1)



Suspicious for papillary carcinoma:

Suspicious carcinoma at resection

Rare intranuclear
inclusions and
abundant colloid -
benign at resection


Indeterminate for papillary carcinoma:

Cases difficult to diagnose

Positive stains
Differential diagnosis