ATYPICAL SQUAMOUS CELLS OF UNDETERMINED SIGNIFICANCE - CORRELATIVE HISTOLOGIC AND FOLLOW-UP-STUDIES FROM AN ACADEMIC-MEDICAL-CENTER

The diagnosis of ASCUS (atypical squamous cells of undetermined signif icance) was introduced in the 1988 Bethesda System for reporting cervi cal/vaginal cytologic findings. Outcome and appropriate management of patients with this diagnosis is not presently established. Criteria de fining ASCUS are nuclear enlargement (2.5-3.0 times normal intermediat e cell nucleus), mild nuclear hyperchromasia, smooth nuclear outlines with mild variation in nuclear size and shape, or else two, but not al l three, cytologic criteria for human papilloma virus (HPV) cytopathic effect. All 668 cases reported as ASCUS from February 1992 - December 1993 from our cytology laboratory were reviewed. These ASCUS cases re presented 4.5% of all gynecologic cases diagnosed in that same time pe riod. Of these, 284 (41%) had a subsequent colposcopic biopsy and/or e ndocervical curettage. The biopsied cases included 101 (36%) with cond ylomata, 38 (13%) with cervical intraepithelial neoplasia (CIN) I, 17 (6%) with CIN II, and 9 (3%) with CIN III. No cases of carcinoma were detected. Of patients with a cytologic diagnosis of ASCUS and subseque nt cervical biopsy, 49% had low-grade cervical intraepithelial neoplas ia (LGSIL), either condyloma or CIN I. Nine percent had high-grade cer vical intraepithelial neoplasia, either CIN II or CIN III. These findi ngs indicate that ASCUS defines cytologically a group of patients who may have either a concurrent or subsequent development of a squamous i ntraepithelial lesion (SIL). This forms a high-risk group. The managem ent of cases with a cytologic diagnosis of ASCUS should be at least as aggressive as that of LGSIL. (C) 1997 Wiley-Liss, Inc.