Diagnostic Cytology
Fig. 8.11 Superficial squamous cell and tall columnar cells
eccentrically located nuclei and abundant cytoplasm. Ciliated cells may be
present (Papanicolaou x OI).
filaments.3 Keratin immunocytochemistry has proved to be a
valuable additional technique in the routine diagnosis of can-
cers that pose problems on morphologic examination. Broad-
spectrum monoclonal antibodies can be used to separate
epithelial tissues from nonepithelial tissues. Combinations of
the 19 different keratin proteins are distributed in a more or less
tissue-specific fashion as initially detected by two-dimensional
gel electrophoresis.2
Mainly based on gel electrophoretic studies, normal ectocer-
vical epithelium was found to contain keratins 1, 4, 5, 6, 13-15,
and 19, with some variability in the expression of keratins 2, 8,
10, 11, 16, and 17. Endocervical cells contain keratins 7, 8, 18,
and 19, with variability in the expression of keratin 4.4 Reserve
cells show an unequivocal distribution of keratin 18 and con-
tain keratins 5, 7, 8, and 14-19. Immature squamous meta-
plasia has a keratin expression pattern that on the one hand is
characteristic of endocervical columnar cells and on the other
hand characteristic of an epithelium that has undergone squa-
mous differentiation. This change becomes emphasized when
we compare immature squamous metaplasia with mature squa-
mous metaplasia. The pattern of keratin expression in immature
squamous metaplasia was shown to differ from that in normal
squamous epithelium. Keratin 19 is present in the full thickness
Fig. 8.12
Sheet of
columnar cells.
Sharply outlined cytoplasmic boundaries
create a honeycomb pattern (Papanicolaou x OI).
of immature squamous metaplastic epithelium, as opposed
to normal squamous epithelium, in which only the basal cell
component reacts positively. Keratins 8 and 18, indicative of a
columnar differentiation of the cells, become absent. The expres-
sion of keratins 4, 10, 13, and 14 increases with squamous dif-
ferentiation (Figs 8.14 and 8.15).5
Puts and co-workers studied the presence of vimentin-positive
cells present in normal ectocervical and endocervical epithelium,
subcolumnar reserve cell hyperplasia, and squamous metaplas-
tic and dysplastic epithelium of the uterine cervix.6 They dem-
onstrated a relatively large number of vimentin-positive and
Langerhans cells in normal ectocervical stratified squamous
metaplastic epithelium, a small number in endocervical colum-
nar epithelium, and a larger number in subcolumnar reserve
cell hyperplasia and in immature squamous metaplasia. Mature
squamous metaplastic epithelium showed a great resemblance
to normal ectocervical stratified squamous epithelium, in both
numbers and distribution of Langerhans cells.
A smear from an atrophic epithelium usually does not cause diag-
nostic problems. Cells are of the basal-parabasal cell type, with a
high nucleocytoplasmic ratio. Cells are often arranged in syncy-
tia with indistinct cell borders. Nucleoli are usually absent.
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