Clinical Significance of a cervical cytologic diagnosis of atypical squamous cells of undetermined significance. Favoring a reactive process or low grade squamous intraepithelial lesion

OBJECTIVE: To define the clinical significance of qualifying the cytologic diagnosis of atypical squamous cells of undetermined significance (ASCUS) as favoring either a reactive process or a low grade squamous intraepithelial lesion (LSIL) in an effort to provide management guidelines. STUDY DESIGN: A total of 118 consecutive nonpregnant women with a cytological diagnosis of ASCUS favoring either a reactive process or LSIL were evaluated in our colposcopy clinic by repeat cervical cytologic smear, colposcopy and colposcopically directed biopsies and/or endocervical curettage, as indicated. RESULTS: Of the 58 patients evaluated for a smear of ASCUS, favoring a reactive process, 5 (8.6%) had cervical intraepithelial neoplasia (CIN) CIN 1 documented by biopsy. None had a high grade lesion. Twenty-six (45%) of the 58 patients who had a cytologic diagnosis of ASCUS favoring a reactive process had a repeat smear that was normal. None was found to have CIN. Of the 60 patients who had a cervical diagnosis of ASCUS favoring LSIL, 9 (15%) had CIN 1 or CIN 2. Nineteen (32%) of the 60 patients who had a cytologic diagnosis of ASCUS favoring LSIL had a repeat smear that was normal. One of these patients had CIN 1 on biopsy. The sensitivity of a repeat smear, in this limited series, after an initial smear of ASCUS favoring a reactive process is 100%, while it was 66% after an initial smear of ASCUS favoring LSIL. CONCLUSION: This study showed that in our laboratory a cytologic diagnosis of ASCUS favoring either a reactive process or LSIL is associated with a very low risk that the patient is haboring CIN. In the patient whose initial smear shows ASCUS favoring a reactive process, a repeat smear that is normal is reassuring. The patient whose smear shows ASCUS favoring LSIL probably requires further evaluation even in the presence of a normal repeat smear.