Efficacy of the cell block technique in diagnostic cytopathology: comparing immunocytochemistry and cytomorphologic preservation on cell block material with conventional cytological preparations
Date
2012
Authors
Khan, Shehnaz
Journal Title
Journal ISSN
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Abstract
Objective
To determine the effectiveness of the cell block technique for immunocytochemical
diagnosis by comparing cytomorphologic preservation and immunocytochemistry (ICC)
stains in paired cell block and conventional fine needle aspiration (FNA) samples.
Study Design
This was a prospective study. Material for both conventional smears and cell blocks were
collected simultaneously during fine needle aspiration of 50 lesions comprising lymph
node, lung and liver masses. Grading of cellularity, morphological preservation,
architectural preservation, immunocytochemical staining intensity and presence of
background staining were compared on paired FNA smears and cell block samples
derived from the same case. Each arm of the paired analysis was performed blindly
without knowledge of the grading outcome of the other. The Kappa statistic (Κ) was used
to measure inter-rater agreement.
Results
The fifty samples evaluated included FNAs from the lung, 24/50 (48%); liver, 23/50
(46%) and lymph node, 3/50 (6%). The immunocytochemistry stains consisted of 44/50
(88%) CK7, 44/50 (88%) CK20, 18/50 (36%) TTF1, 10/50 (20%) synaptophysin, 10/50
(20%) Hepar-1 and 7/50 (14%) AE1/3. There was no overall agreement in preservation
of cytomorphological detail and ICC staining between the two methods. The
Papanicolaou stained conventional FNA smears fared better then cell block for the
vi
evaluation of nuclear and cytomorphologic characteristics; cells in the cell block were
poorly preserved in many cases. The ICC stains worked better on the cell block samples
due to lack of background and aberrant staining.
Conclusion
Conventional FNA smears and cell blocks complement each other. Our results indicate
that it would be optimal to use both modalities in the diagnostic work-up of mass lesions
amenable to FNA diagnosis; the former to assess morphology, and the latter for optimal
immunocytochemistry results. In resource constrained settings, the cost implications of
performing both conventional and blocked smears on all FNA material warrants further
evaluation.
Description
A dissertation submitted to the Faculty of Health Sciences, University of Witwatersrand,
in fulfilment of the requirements for the degree
of
Master of Science (Medicine) in the branch of Anatomical Pathology
Johannesburg, 2012
Keywords
cell block, FNA smears, immunocytochemistry, cytomorphology