Atypical squamous cells of undetermined significance. A cytohistologic study of 52 cases.
OBJECTIVE
To evaluate the significance of atypical squamous cells of undetermined significance (ASCUS) by correlating the histologic findings following a diagnosis of ASCUS on a cervical cytologic smear.


METHODS
Eighty-four smears that had been called ASCUS over a five-month period and that had corresponding histologic material were reviewed independently. Only 52 of the 84 cases on which a consensus was reached were retained for the current study.


RESULTS
The breakdown of the follow-up histologic diagnoses was as follows: 28 cases (54%) were negative (without squamous intraepithelial lesions [SIL]); 22 cases (42%) showed SILs, of which 14 (27%) were low grade, 5 (10%) were high grade and 3 (5%) had SILs that could not be further classified because of fragmentation of the endocervical curettings. Finally, two cases (4%) proved to be invasive cervical carcinoma on histology despite smears that were satisfactory and not limited by the quantity or quality of material; in these the discrepancy was attributed to sampling error.


CONCLUSIONS
Patients whose cervical cytologic smears fall into the category of ASCUS may, on follow-up, exhibit a wide spectrum of findings, ranging from no pathologic abnormality to frequent SIL and even to invasive carcinoma in rare instances. A diagnosis of ASCUS on smears warrants careful follow-up and investigation.
Auger
M
M
Department of Pathology, Royal Victoria Hospital, McGill University, Montreal, QC, Canada.
Charbonneau
M
M
Arseneau
J
J
D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D002584:Cervix Uteri / Q000166:cytology* / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008679:Metaplasia; D012189:Retrospective Studies; D002577:Uterine Cervical Diseases / Q000473:pathology*; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D002575:Uterine Cervicitis / Q000473:pathology; D014626:Vaginal Smears