5
Evaluation of the Sample in Smears and Liquid-Based Preparations
Fig. 5.10
Cluster of malignant cells and granular tumor diathesis in
endometrial adenocarcinoma.
Thinprep (papanicolaou x Mp).
Fig. 5.12
Nuclear grooves, chromatin clearing, margination and
three-dimensional effect in
papillary thyroid carcinoma
FNA. Millipore
filter (papanicolaou x Hp).
Fig. 5.11
Follicular architecture in
follicular thyroid adenoma
FNA. Direct
smear (Diff Quik x Mp).
sialadenitis from Warthin's tumor in which characteristic large pap-
illary oncocytic lymphoepithelial tissue fragments are best appreci-
ated and often only appear in the cell block pellet derived from
needle rinses (Fig. 5.16).16 Similarly, cell blocks have been reported
to be extremely helpful in discerning malignant papillary tissue
fragments containing fibrovascular cores from benign papillary
tissue fragments that for the most part lack fibrovascular cores.17
Also the characteristic Orphan Annie-eyed nuclear chromatin pat-
tern (felt by some to be a useful reproducible histologic artifact)
is best seen in cytology specimens that have been conventionally
processed into formalin-fixed paraffin-embedded cell blocks.18-21
In a study by Sanchez and Selvaggi additional morphologic infor-
mation derived from cell blocks was found to be
diagnostically con-
tributory in 31 % thyroid FNAs.22
In addition to its unique ability to
provide essential histologic clues cell blocks offer in theory and
often in practice the opportunity to perform the same
battery of
ancillary studies
as conventionally processed surgical biopsy tissue
including molecular analysis and electron microscopy.23,24
Fig. 5.13
True
monolayer of benign urothelial cells
in clear background
in voided urine. thinprep (papanicolaou x Mp).
A few published reports document the fact that immunocyto-
chemistry can be performed successfully on Cytospin, ThinPrep,
Millipore filter, and direct smear slides.25-28 Options are some-
what limited in terms of the number and types of antibodies
available due to the typically sparse and delicate nature of the
cellular material present in these preparations. Many articles, on
the other hand, describe the diagnostic usefulness of a variety of
immunohistochemical stains on cell block material.29-38 In par-
ticular, paraffin-embedded cell blocks have proven efficacious
by helping to resolve benign reactive lesions from both primary
and metastatic tumors (Fig. 5.17). Such common dilemmas
may often require a panel of immunohistochemical stains. See
Chapter 35 for additional information.
Comparison of Nongynecologic Processing Techniques
There are many articles found in the contemporary literature
which compare the efficacy of the processing modalities based
on costs, cellular yield, unsatisfactory rates, artifacts, and diagnos-
tic accuracy. Most deal with specific types of specimens such as
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