Evaluation of mild-to-moderate dysplasia on cervical-endocervical (Pap) smear: a subgroup of patients who bridge LSIL...

The Bethesda System recommends Pap smear diagnosis to be based on the most abnormal cells present, regardless of number. Our reporting system includes a diagnostic category of mild-to-moderate dysplasia (D1-2), defined as cases with only a few moderately dysplastic cells. We evaluated the validity of a D1-2 diagnostic category by reevaluation of 58 cases with subsequent follow-up (up to 24 months). On biopsy and/or Pap smear follow-up, 24 cases (41%) showed LSIL and 34 cases (59%) showed HSIL. Index smears from these cases were examined by two cytopathologists blinded to patient follow-up for the following morphologic features: volumes (scale 1-4) of LSIL, HSIL, and dyskeratosis, HSIL as single cells or syncytial fragments, and acute inflammation. None of the morphologic features evaluated were significantly different between the LSIL and HSIL follow-up groups based on univariate and multivariate logistic regression analysis. The diagnosis of D1-2 on Pap smear is a valid diagnostic category that defines a subgroup of patients with both LSIL and HSIL follow-up, which cannot be reliably predicted based on morphology alone.