Clinical Significance of Atypical Squamous and Glandular Cell Lesions in Cervical Smear Screening Cytology: A Two-Year Follow-Up Study in an Iranian Population.

Background & objective: Atypical squamous cells (ASC) are the most common epithelial abnormalities found in cervical cytology reports. The clinical significance of ASC and atypical glandular cells (AGC) varies, making clinical management and follow-up challenges.

Methods: All women diagnosed with ASC or AGC in the past 4 years and referred to a tertiary hospital were included. The study evaluated regression, persistence, or progression to significant abnormalities over a two-year follow-up period.

Results: Out of 22,386 cervical cytology smears, 208 (4.8%) patients were diagnosed with ASC (ASC-US: 3%, ASC-H: 1.8%) or AGC (0.25%). Among ASC-US patients with documented follow-up, 11 (46%) showed significant abnormalities, while 13 (54%) showed insignificant abnormalities. In the ASC-H group, with available follow-up, 20 (72%) showed significant abnormalities, and 8 (28%) showed insignificant abnormalities. When considering ASC-US and cervical intraepithelial neoplasia 1 (CIN 1) as low-grade lesions, 19 (31%) patients with ASC-H had low-grade, and 13 (69%) had high-grade abnormalities. In the ASC-US group, 10 (99%) patients had low-grade lesions, while only 1 (1%) had high-grade lesions. Among AGC, not otherwise specified (NOS) patients with follow-up, 17 (65%) had significant lesions, and 9 (35%) had insignificant lesions. All 13 patients with AGC, favor neoplastic (FN)/adenocarcinoma in situ (AIS), showed significant lesions.

Conclusion: While patients diagnosed with ASC-H and AGC are at a higher risk for significant lesions, ASC-US patients may also develop significant lesions. Thus, ASC-US is clinically significant, and these patients should be closely monitored.