Cytologic evaluation of tissue aspirates, impressions or scrapings offers
a rapid assessment of tissue pathology and is often a practical in-clinic
diagnostic tool that has the ability to offer a diagnosis, aid in
prognostication, direct therapeutic interventions and suggest further
diagnostic testing. The ability of the sample to meet all of these goals
relies on proper collection technique, slide preparation and staining, as
well as the nature and distribution of the lesion and the skill/experience
of the cytologist. Even the most experienced clinical pathologist will not
be able to reach an accurate diagnosis if the cellularity of the sample is
too low, if the smear is too thick or if the aspirated tissue is not
representative of the observed lesion. In addition, some lesions cannot
be diagnosed cytologically despite proper collection, smear preparation
and staining, as tissue architecture may be required or cells may not
exfoliate readily from some lesions. In these cases histopathology is
necessary.