Rapid on-site evaluation and cell blocks: getting the most from the least invasive method in cytopathology

Fine needle aspiration cytology (FNAC) sampling is a minimally invasive procedure done to identify the pathology behind superficial and deep-seated lesions. Rapid on-site evaluation (ROSE) can be an adjunct to the FNACs. Our study aimed to identify the role of ROSE in diagnostic adequacy and to check the benefit of cell block (CB)/cell buttons prepared from the ROSE samples.

A prospective study was conducted where all patients referred for FNAC were included. ROSE using 1% aqueous toluidine blue stain and CB/cell button preparations were done for the identification of various cytological lesions.

Among 600 cases included in the study most common age group was third and fourth decades with a mean age of 41.6 years and M: F ratio of 1:1.7. Ultrasound-guided procedures were done in 20% of cases. CB preparation was available in 14% of cases. Most CBs were from the cases wherein ROSE was performed 81% (77 out of 86), with CB helping in making an accurate diagnosis in 17% of cases. Lymph nodes 26%, and thyroid 23% were the most common sites for sampling with the highest number of repeat procedures from non-ROSE cases (14%). The non-diagnostic rate for non-ROSE cases was 7.7% (23/300) even after the repeat procedures as compared to 1.3% (4/300) for ROSE. Three slides on average were consumed in ROSE-performed procedures, as compared to an average of 5 slides in non-ROSE. The average turnaround time was 1.7 days for non-ROSE cases and 1.05 for ROSE cases respectively. Cyto-histopathological correlation was available in 40% of cases with a sensitivity of 98.1%, specificity of 96.7%, positive predictive value of 90%, negative predictive value of 99.4%, and diagnostic accuracy of 97%. The correlation of CB, number of slides consumed, and turnaround time among the 2 groups were statistically significant (P value < 0.001).

ROSE is a method used to assess material aspirated at the time of FNAC procedures to determine the adequacy and to an extent to identify whether the lesion is neoplastic or non-neoplastic. CBs have helped in increasing diagnostic accuracy apart from the fact that the paraffin-embedded tissue material can be used for further studies.