Abnormal Pap Smear: Atypical Squamous or Glandular Cells of Undetermined Significance

Introduction

• Description: One of the most perplexing aspects of management under the Bethesda reporting system is how to interpret smears reported as showing atypical squamous or glandular cells (ASCUS, ASCH, or AGC). The atypical squamous cell (ASC) diagnosis has been developed to describe squamous cell changes that are more severe than reactive changes but not as marked as those found in squamous intraepithelial lesions (SIL, high and low grade [HSIL and LSIL]). The ASC designation has been subdivided into “atypical squamous cells of undetermined significance” (ASCUS) and “atypical squamous cells cannot exclude HSIL” (ASCH). The latter includes the cytologic changes suggestive of HSIL but insufficient for a definitive diagnosis. The category of atypical glandular cells (AGC) includes a range of findings from benign reactive changes in endocervical or endometrial cells to adenocarcinoma.

• Prevalence: ASC—approximately 3% of all Pap tests; AGC—0.2% of all Pap tests.

• Predominant Age: Reproductive age.

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: If not all, most of the changes seen result from infection by the human papillomavirus (HPV). The AGC diagnosis reflects benign reactive changes in endocervical or endometrial cells, endometrial hyperplasia, or adenocarcinoma.

• Risk Factors: ASC—exposure to high-risk HPV. AGC—none known, except for those affecting possible pathologic causes (eg, unopposed estrogen therapy as a risk factor for endometrial carcinoma).

Signs and Symptoms

• Asymptomatic

Diagnostic Approach