Diagnostic Value of Preparing Additional Liquid-Based Cytology Slides and Cell Blocks from Residue Material in Thyroid fine Needle Aspiration.

Background and aims: After liquid-based cytology (LBC) technique developed for cervical cytology, it has been used for nongynecological samples and has been very successful. It offers having extra slides of the samples for further examination and ancillary tests. Moreover, cell blocks can be formed from the residue material. The study aimed to evaluate the importance of preparing a second LBC slide or a cell block from the residue material of thyroid fine needle aspiration (FNA) samples to reach a definitive diagnosis in cases diagnosed as nondiagnostic (ND) after the first slide.

Material and methods: Seventy five cases diagnosed as ND after the first slide were included in study. For 50 cases, the second LBC slides were prepared (LBC group); for 25 cases, cell block was performed from residue material (CB group). Two groups were compared in terms of reaching a definitive diagnosis.

Results: At the end of secondary procedures, a definitive diagnosis was reached in a total of 24 cases (32%). Twenty of 50 cases (40%) in LBC group reached a definitive diagnosis while four cases (16%) in the CB group reached a definitive diagnosis. Achieving a definitive diagnosis was found statistically higher in the LBC group in which the second slide was formed compared to the CB group (P =0.036).

Conclusion: Preparing a second slide with LBC method is more purposive than preparing a cell block from the residue material of thyroid FNA samples. Reducing the percentage of ND cases will protect patients from complications and morbidity that may arise from repeated FNA.