8
Benign Proliferative Reactions, intraepithelial Neoplasia, and invasive Cancer of the Uterine Cervix
Fig. 8.9
Mucus-producing
columnar cells
lining the endocervical
canal (H&E x HP).
Fig. 8.10
Low-power view of the
uterine cervix.
Deep stromal
invaginations of endocervical mucosa greatly increase the surface of the
mucus-producing columnar epithelium (H&E x LP).
or coarsely vacuolated, faintly cyanophilic, clear cytoplasm
(Fig. 8.11). Ciliated cells may be present. Endocervical cells usu-
ally are arranged in strips of parallel-arranged cells or in tight
sheets. When present in sheet-like arrangements, cell boundaries
may create a honeycomb pattern (Fig. 8.12). It is not unusual to
find stripped, bare nuclei due to lysis of the fragile cytoplasm.
Basally located nuclei are round to oval and often rather vari-
able in size, with a finely granular, evenly distributed chroma-
tin. In most nuclei, one or two small nucleoli can be observed.
In cases of increased proliferative activity of the endocervical
epithelium, the cells and their nuclei show a rather wide varia-
tion in size and shape and nucleoli may become prominent and
variable in size. Multinucleation of cells is not uncommon. In
well-preserved cytologic specimens, ciliated columnar cells may
be recognized. The morphologic variants of ciliated and mucus-
producing cells refer to the mullerian origin of the endocervical
epithelium. The presence of ciliated cells has no special signifi-
cance. It is therefore no sign of an epithelial abnormality.
In tissue sections, a single layer of primitive cells can often be
observed beneath the columnar cell layer. These cells, also called
reserve cells,
are thought to be multipotential germinative cells,
which under physiologic conditions produce normal endocervi-
cal columnar cells (Fig. 8.13). In pathologic states, reserve cells
may proliferate and, depending on the severity of the stimulus,
produce abnormal, less well-differentiated columnar cells or,
through the process of metaplasia, squamous metaplastic cells.
Immunocytochemistry of Normal Cervical Epithelium
The structure and shape of a cell are maintained by an internal
cytoplasmic structure, the cytoskeleton. In this cytoskeleton, on
the basis of their ultrastructural appearance and biochemical
composition, three different types of filaments can be distin-
guished. Next to microtubules and microfilaments, filaments
measuring 8 to 11 nm in diameter are commonly seen in mam-
malian cells. These so-called
intermediate-sized filaments,
which
are extremely insoluble and have a biochemical composition
entirely different from that of microtubules and microfilaments,
often constitute a considerable part of the intracellular matrix.
There are five types of intermediate filaments, and they occur in
tissue-specific combinations.2,3
Keratins have been recognized as epithelium-specific inter-
mediate filament proteins and as comprising a family of at least
19 different polypeptides (not including the hair keratins). The
tissue-specific intermediate filament proteins are retained dur-
ing malignant transformation. Tumors of epithelial origin thus
retain cytokeratin as the structural protein for the intermediate
135
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