Reappraisal of cytology-histology correlation in cervical cytology based on the recent American Society of Cytopathology guidelines (2017) at a cancer research centre.

Abstract

To assess the impact of recently published American Society of Cytopathology (ASC) guidelines (2017) on the conduct of cervical cytology-histology correlation (CHC). A retrospective review was conducted for cervical biopsies with their corresponding conventional cervical smears over a 7.5-year period (January 2011-June 2018). As per the ASC guidelines, a discrepancy assessment grid was prepared. Major cytology-histology discordance was defined as a diagnosis of high-grade squamous intraepithelial lesion (HSIL) or CIN2+ in one of the tests with negative result in the other. Smears and biopsies of all discordant cases were reviewed for reasons of overcall and undercall. Of the 341 cervical biopsies with corresponding Papanicolaou smear, cytology-histology agreement was noted in 249 (73%) cases. Major discordance was observed in 22 cases (6.4%)-16 undercalls and six overcalls on cytology-while minor discrepancies were noted in 70 cases. Atypical metaplasia and repair changes were the main reasons for overcall while small HSIL cells in atrophic smear and scant HSIL cells were important causes of undercall on cytology review. Using the ASC guidelines, we could improvise upon the existing CHC methodology for categorisation of cyto-histological pairs of cases with a cytological diagnosis of atypical glandular cells. The present study demonstrates, for the first time, that the recent ASC guidelines facilitate cervical CHC, especially for categorisation of cases with atypical glandular cells on cytology. Uniform application of these guidelines would standardise the conduct of cervical CHC internationally and provide scope for inter-laboratory comparison of data as well as enhance self-learning and peer learning.