Cell Block Preparation as a Diagnostic Technique Complementary to Fluid-Based Monolayer Cervicovaginal Specimens

To determine whether preparation of cell blocks from fluid-based cervicovaginal specimens can add to the diagnostic accuracy of monolayer preparations from the same specimens. Cell block preparations were made from 100 cervicovaginal, fluid-based ThinPrep Pap test specimens. These specimens were collected in a fluid-based solution with a Papette or cytology brush and a scraper. After a monolayer slide was made, a determination was made if a cell block preparation was needed based on the morphologic findings on the slide. Cell block results aided the ThinPrep Pap diagnosis in 20% of specimens and were critical to the diagnosis in 5%. The cell block preparation was most useful in lesions where architecture and morphology were important, such as immature squamous metaplasia versus high grade squamous intraepithelial lesion, repair versus squamous carcinoma and tubal metaplasia versus atypical glandular cells of undetermined significance. It was also found that the presence of tissue fragments rather than single cells on the slide was an indication of the possibility that a cell block was productive. Cell block preparation in selected cases can be a valuable adjunct to monolayer slide preparations in the diagnosis of cervicovaginal lesions.