Atypical cells thought to be of endocervical glandular origin often ca
use diagnostic uncertainty in cervicovaginal smears. For this reason c
onsecutive cases of endocervical glandular atypia diagnosed in smears
were correlated with subsequent biopsy diagnoses and then retrospectiv
ely reviewed. Smears were originally diagnosed as ''mild glandular aty
pia, probably reactive'' or ''severe glandular atypia, suggestive of a
denocarcinoma in situ'' (AIS). Biopsy follow-up was obtained on 34 of
58 patients diagnosed with severe endocervical glandular atypia. Nine
patients (26%) had AIS, three with concomitant high-grade squamous int
raepithelial lesions (HSIL) and two with invasive adenorarcinoma. Eigh
teen patients (53%) had HSIL only. Seven had benign changes. Of 152 pa
tients diagnosed with mild glandular atypia, biopsy follow-up was obta
ined on 40. One patient had AIS; 14 (35%) had HSIL; one had low-grade
SIL (LSIL); and 24 (60%) had benign changes. Blinded review of these s
mears yielded results similar to those in the biopsy follow-up, that i
s, the prediction of AIS on smears included most cases of AIS, some in
vasive adenocarcinomas, a significant number of HSIL cases and a few b
enign lesions. A review diagnosis of ''reactive glandular cells'' prov
ed to be HSIL in 31% of cases and AIS in one case. We conclude that pa
tients with a diagnosis of severe glandular atypia in smears may prove
to have AIS or invasive adenocarcinoma, but often have HSIL without c
oncomitant AIS. ii? addition, although ''reactive'' glandular atypia i
n smears usually reflects a benign condition, a significant minority o
f such patients prove to have HSIL. (C) 1995 Wiley-Liss, Inc.