Degree of nuclear enlargement is more variable than in LSIL.
Chromatin may be fine or coarsely granular and evenly distributed.
Contour of nuclear membrane is quite irregular with frequently prominent indentations or grooves.
Nucleoli are generally absent, but may occasionally be seen, particularly when HSIL extends into endocervical gland spaces.
Appearance of cytoplasm is variable; it can appear “immature”, lacy, and delicate or densely metaplastic; occasionally the cytoplasm is “mature” and densely keratinised.
Relatively few cells may be present; often as isolated single cells and less commonly in aggregates.
Marked variation in cellular size and shape is typical, with caudate and spindle cells that frequently contain dense orangeophilic cytoplasm.
Nuclei vary markedly in size, nuclear membranes may be irregular in configuration, and numerous dense opaque nuclei are often present.
Chromatin pattern, when discernible, is coarsely granular and irregularly distributed with parachromatin clearing.
Macronucleoli may be seen but are less common than in nonkeratinizing squamous cell carcinoma.
Associated keratotic changes (“hyperkeratosis” or “pleomorphic parakeratosis”) may be present but are not sufficient for the interpretation of carcinoma in the absence of nuclear abnormalities.
A tumour diathesis may be present, but is usually less than that seen in nonkeratinizing squamous cell carcinomas.
Nonkeratinizing Squamous Cell Carcinoma
Cells occur singly or in syncytial aggregates with poorly defined cell borders.
Cells are frequently somewhat smaller than those of many HSIL, but display most of the features of HSIL.
Nuclei demonstrated markedly irregular distribution of coarsely clumped chromatin.
A tumor diathesis consisting of necrotic debris and old blood is often present.
Large cell variant tumors may show prominent macronucleoli and basophilic cytoplasm.