Abnormal Pap Smear: Low-Grade Squamous Intraepithelial Lesions and High-Grade Squamous Intraepithelial Lesions

Introduction

• Description: Low-grade squamous intraepithelial lesions (LSILs) encompass changes associated with human papillomavirus (HPV), mild dysplasia, and cervical intraepithelial neoplasia (CIN) 1. High-grade squamous intraepithelial lesions (HSILs) include CIN 2 and 3 and carcinoma in situ (CIS). Patients with low-grade CIN are unlikely to develop cervical malignancy, whereas those with high-grade lesions are at high risk of progression to malignancy.

• Prevalence: Less than 1% of Pap tests for low-grade abnormalities and 0.2% for high-grade abnormalities.

• Predominant Age: Reproductive age.

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: HPV appears to be responsible for the development of cervical dysplasia. Although as many as 70% of invasive cervical cancers have HPV serotypes 16 or 18 present, these types also may be detected in patients with LSILs. Unaffected patients have HPV prevalence rates that vary from 10%–50%, depending on the study technique and population evaluated.

• Risk Factors: Exposure to HPV and other sexually transmitted infections; smoking is associated with a higher risk. Smoking and immunosuppression are associated with a higher risk of progression.

Signs and Symptoms

• Asymptomatic

Diagnostic Approach