Solution - Cytology Mystery #6
The smear is satisfactory for interpretation, with adequate
squamous cellularity and endocervical cells present. Atrophic changes are noted. Parabasal
cells are present singly and in small clusters and sheets. Some hyperchromatic groups with
marked crowding and a syncytial appearance are seen.
Diagnosis: High-grade squamous dysplasia (CIN III - severe
dysplasia/carcinoma in situ).
It can be difficult to differentiate atrophic changes from high-grade dysplasia,
especially if the smear is poorly preserved. In general, caution is advised when
air-drying artifact is prominent. In better-fixed smears (such as this one), the chromatin
of dysplastic cells has a crisp, variably coarse texture. Carcinoma in situ and invasive
carcinoma feature markedly abnormal architecture with disorder and overlapping of nuclei.
Atrophy may be characterized by considerable nuclear enlargement (up to 3-5 times the area
of a normal atrophic squamous cell nucleus) but the chromatin is bland to smudgy. Atrophic
smears may also contain parakeratotic-like cells, small orangeophilic squames with
pyknotic nuclei and typically rounded cytoplasmic contours, which are scattered over the
smear. So-called "blue blobs" may simulate large dysplastic or malignant nuclei
- these are though to represent either inspissated mucus or hematoxylin precipitating on
degenerating atrophic squamous cells. Blobs, degenerated blood and granular debris form a
"diathesis" in marked atrophy which can simulate the diathesis of invasive
carcinoma.
Borderline atypias may be signed out with a recommendation for topical estrogen therapy,
following which non-dysplastic cells will show maturation on a repeat smear, but true
dysplasia will be unaffected. Since the transition zone can be located high in the
endocervical canal in older patients, both cytologic scrapings and biopsy may not
adequately sample the lesion.
In cases where atypical crowded parabasal-type groups are worrisome, it pays to examine
the smear carefully to find the best-preserved areas, and to seek out individual
dysplastic or malignant squamous cells rather than focusing exclusively on groups of
cells. This can be very helpful in confirming the presence of a significant problem, and
to differentiate squamous and glandular lesions.