BACKGROUND. Squamous atypia in postmenopausal (PM) cervical vaginal sm
ears (CVS) only rarely is associated with a biopsy-proven squamous int
raepithelial lesion (SIL), and thus most commonly represents an atroph
y-associated benign reactive change. METHODS. To distinguish atypical
squamous cells of undetermined significance (ASCUS) and SIL from atrop
hy-associated benign reactive changes, a review of atypical atrophic P
M CVS was performed. Ninety CVS exhibiting an atrophic smear pattern w
ere considered appropriate for study. Repeat smears and/or biopsy afte
r local estrogen therapy were requested to distinguish atrophic/reacti
ve from dysplastic changes. RESULTS. Generally, atrophic CVS exhibit u
niform nuclear enlargement in the squamous cell population, which, usi
ng the criterion of nuclear enlargement alone, would qualify the major
ity of these cases to be classified as ASCUS. The nuclear enlargement
associated with atrophy resolves with the local application of estroge
n. Follow-up after local estrogen treatment was available for 84 of 90
patients and revealed 10 cases of SIL (12%) and 9 cases of ASCUS (11%
), 6 of which were favored to be of a reactive etiology. Nuclear featu
res most commonly noted in the cases considered to be ASCUS (nonreacti
ve) and SIL were nuclear hyperchromasia and nuclear contour irregulari
ties. CONCLUSIONS. Nuclear enlargement alone is not sufficient for dia
gnosing ASCUS or SIL in PM CVS. Nuclear enlargement in squamous cells
is an expected normal reactive change present in PM CVS that resolves
with the application of local estrogen. Nuclear hyperchromasia and irr
egular nuclear contours remain the most reliable cellular characterist
ics for diagnosing SIL in atrophic CVS. [See editorial on pages 200-1,
this issue.] Cancer (Cancer Cytopathol) 1998;84:218-25. (C) 1998 Amer
ican Cancer Society.