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 findin gs following a diagnosis of ASCUS on a cervical cytologic smear. STUDY DESIGN: Eighty-four smears that had been called ASCUS over a five-mon th period and that had corresponding histologic material were reviewed independently. Only 52 of the 84 cases on which a consensus was reach ed were retained for the current study. RESULTS: The breakdown of the follow-up histologic diagnoses was as follows: 28 cases (54%) were neg ative (without squamous intraepithelial lesions [SIL]); 22 cases (42%) showed SILs, of which 14 (27%) were low grade, 5 (10%) were high grad e 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 t hat were satisfactory and not limited by the quantity or quality of ma terial; in these the discrepancy was attributed to sampling error. CON CLUSION: Patients whose cervical cytologic smears fall into the catego ry of ASCUS may, on follow-up, exhibit a wide spectrum of findings, ra nging from Mo pathologic abnormality to frequent SIL and even to invas ive carcinoma in rare instances. A diagnosis of ASCUS on smears warran ts careful follow-up and investigation.