5
Evaluation of the Sample in Smears and Liquid-Based Preparations
Table 5.1
Artifacts more commonly seen with nongynecologic LBp
Cellularity
Nuclear
Background
Cellular shrinkage
Increased naked
nuclei
Loss of adipose tissue,
stroma, mucin, and
colloid
Disruption of tissue
fragments
Decreased nuclear
chromatin details
Colloid that appears
as dense droplets
Flattening and
fragmentation of large
cellular sheets
attenuation of nuclear
grooves and pseudo
inclusions
aggregation
of lymphocytes
Formation of cell
clusters
Exaggerated nucleolar
prominence
artificially increased
single epithelial cells
Fig. 5.18
Dense
colloid droplet
in thyroid FNA in goiter. Thinprep
(papanicolaou x Mp).
Fig. 5.19
Benign ductal cells in association with
myoepithelial cells.
Thinprep (papanicolaou x Mp).
Fig. 5.20
High-grade
urothelial carcinoma.
Cytospin (papanicolaou x Mp).
to the ThinPrep method for FNA specimens are the inability
to assess cellularity of individual passes; diminished/distorted
extracellular and stromal elements such as mucin, stroma, adi-
pose tissue, and colloid that also appeared as dense droplets (Fig.
5.18); crowded tight tissue clusters with loss of cellular preser-
vation; increased cellular and tissue fragment disruption; artifi-
cially increased single epithelial cells; numerous naked nuclei;
pronounced nucleoli; decreased nuclear details; and attenu-
ation of nuclear grooves and pseudo-inclusions. Authors did
note that significantly more conventional smears were limited
by air-drying artifact. Additionally, ThinPrep slides had greater
cellularity, improved nuclear detail, and more easily recogniz-
able myoepithelial cells relative to direct smears (Fig. 5.19). An
added benefit of greater suitability for immunoperoxidase stain-
ing was also documented for ThinPrep processing.48
Specific examples in which artifact-associated ThinPrep-
processed FNA slides
compromised diagnostic accuracy
were cited:
Four out of 21 fibroadenomas were correctly diagnosed on Thin-
Prep-processed breast FNA due to artificially increased single
ductal epithelial cells and a lack of background stroma.47 Three
benign pancreatic lesions were interpreted as atypical/suspicious
due to presence of single atypical cells with distinct nucleoli,
and one mucinous pancreatic neoplasm was incorrectly diag-
nosed due to lack of background mucin.51
The diagnostic value for pleural fluid specimens of ThinPrep
versus Cytospin was compared by examining a large spectrum
of cytologic features that would distinguish malignant meso-
thelioma (e.g., peripheral cytoplasmic skirt, bubbly cytoplasm,
cyanophilic cytoplasm, and scalloped border of cell balls) from
pulmonary adenocarcinoma (e.g., two-cell population, inspis-
sated cytoplasmic material, cytoplasmic vacuole, angulated
and indented nuclei, and smooth border of cell balls).54 Based
on statistical analysis most cytologic features examined in this
study can be seen in both preparation techniques. The authors
therefore concluded that ThinPrep preparation of pleural effu-
sions does not appear to provide additional diagnostic value
when compared to Cytospin preparation.
A comparative analysis of urine specimens processed by
both ThinPrep and Cytospin techniques found that the cyto-
morphology and screening time were comparable with both
techniques.55 However, in cases of transitional cell carcinoma
Cytospin was superior in terms of better preservation of archi-
tectural features and produced less artificial empty spaces and
air-drying artifact (Fig. 5.20). A contrasting study compared
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