Role of liquid based cytology vs. conventional cytology in FNAC of abdominal masses

The study was conducted to assess the role of Thin Prep, one of the FDA approved Liquid based cytology techniques in the diagnostic cytology work up of abdominal masses. We evaluated a total of 30 patients presenting with abdominal masses. The aspirate material was processed by conventional technique and by Thin Prep method and also rinsed into cell block fluid. The slides prepared from both the methods were compared by two independent pathologists. They were evaluated by comparing adequacy, cellularity, architectural pattern, cellular morphology preservation and background. Findings suggested that cellularity was more often higher in conventional smears than on Thin Prep slides (p value=0.025). Architectural pattern preservation was better on conventional smears (p value=0.001). Cytoplasmic preservation was better on conventional smears (p value=0.001), but difference in preservation of nuclear details was not statistically significant. The background in smears prepared by Thin Prep slides were significantly cleaner than direct smears (p value=0.001). Non epithelial elements like mucin and neurofibrillary tangles were better preserved on direct smears (p value=0.001), but diagnostic accuracy for both the methodologies showed no statistically significant difference (p value=0.226). The Liquid based cytology techniques utilize expensive equipment, reagents and they also generate certain morphological artifacts in slides with which a cytologist needs to get familiar. On using alone they might not consistently provide any added benefit in the work up of such lesions and should be employed as an adjunct to conventional smears. They may be preferred in situations where material needs to be transported or is required for ancillary tests.