Page 287 - Textbook of Pathology, 6th Edition

271

CHAPTER 11

Figure 11.4 L-SIL. The smear shows koilocytes having abundant Figure 11.5 H-SIL. The squamous cells have scanty cytoplasm and Basic Diagnostic Cytology
vacuolated cytoplasm and nuclear enlargement (arrow). markedly hyperchromatic nuclei having irregular nuclear outlines. The
background shows numerous PMNs.
in size, with ingested erythrocytes and a round eccentric the precancerous state, they were collectively termed ‘cervical
nucleus with a central karyosome. intraepithelial neoplasia’ (CIN) and categorised as under
NEOPLASTIC EPITHELIAL CELL ABNORMALITIES: (also see Fig. 24.5):
Carcinoma of the uterine cervix still ranks high in the list as CIN I Mild Primitive (atypical) cells,
the most frequent cancer in developing countries of the world dysplasia proliferating in lower
and is the leading cause of cancer morbidity and mortality. third of epithelium.
Vast majority of cervical cancers are of the squamous cell CIN II Moderate Involvement up to
type, and the diagnosis of squamous cell carcinoma of the dysplasia middle-third of epithelium.
cervix and its precursor lesions is considered as the most CIN III Severe Involvement of upper-third
important application of exfoliative cytology. dysplasia of epithelium.
Neoplastic epithelial changes are described below under
2 headings: squamous cell abnormalities and glandular cell Carcinoma Involvement of full
abnormalities. in situ (CIS) thickness of epithelium.
1. SQUAMOUS CELL ABNORMALITIES: The fully- Presently, the Bethesda system divides squamous cell
developed invasive squamous cell carcinoma of the uterine abnormalities into four categories:
cervix is preceded by a pre-invasive intraepithelial neoplastic Atypical squamous cells of undetermined significance
process that is recognisable on histologic and cytologic (ASCUS) which represents cellular changes falling short of
examination. intraepithelial lesion.
Morphogenesis and nomenclature. The earliest recognisable Low-grade squamous intraepithelial lesion (L-SIL) that
change is hyperplasia of basal or reserve cells which normally includes CIN-I and cellular changes associated with HPV
constitute a single layer at the deepest part of the epithelium. infection.
The proliferating reserve cells next develop certain atypical High-grade squamous intraepithelial lesion (H-SIL) includes
features i.e. hyperchromasia and increased nuclear size. The CIN grade II, III and CIS.
continued proliferation of these atypical cells with loss of Squamous cell carcinoma.
polarity, a concomitant increase in mitotic activity, and
progressive involvement of more and more layers of the Cytomorphology. Precancerous states can be distinguished
epithelium is known as dysplasia (disordered growth). When from invasive carcinoma on the basis of cytomorphological
dysplasia involves the full thickness of the epithelium and features observed in smears. In dysplastic epithelium,
the lesion morphologically resembles squamous cell stratification and maturation of cytoplasm occurs above the
carcinoma without invasion of underlying stroma, it is layers of proliferating primitive cells while the nuclear
termed carcinoma in situ (CIS). CIS further evolves through abnormalities persist. Cells exfoliating from the surface, thus,
the stage of microinvasive carcinoma (with depth of stromal display cytoplasmic maturation and differentiation with
invasion not exceeding 3 mm) into full-blown invasive nuclear atypia and are known as dyskaryotic cells.
squamous cell carcinoma. The character and type of dyskaryotic cells observed in
Previously depending on the degree of epithelial smears reflect the severity of dysplasia:
involvement, three grades of dysplasia were recognised: In mild dysplasia (CIN-I or L-SIL), maturation occurs in
mild, moderate and severe. As the stages of dysplasia and the upper two thirds of the epithelium and exfoliated
CIS represented a continuous spectrum of lesions seen in dyskaryotic cells are of the superficial type. These cells show