Improving Detection Efficiency of FNAC and BRAF V600E Mutation in Thyroid Nodules Using Pipette Mixing: A Retrospective Study.

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common endocrine malignancy, with a significant subset of cases harboring the BRAF V600E mutation. Fine-needle aspiration cytology (FNAC) combined with BRAF V600E mutation detection is a standard diagnostic approach for thyroid nodules. However, sample heterogeneity often leads to inconsistent results between cytological and molecular analyses. This study aimed to evaluate whether pipette mixing of FNAC samples improves the detection efficiency and diagnostic accuracy of the BRAF V600E mutation in thyroid nodules.

METHODS

A retrospective analysis was conducted on 360 FNAC samples, divided into pipette-mixed group (n = 180) and a non-mixed group (n = 180). Samples were classified using The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC), and BRAF V600E mutation status was assessed using ARMS-PCR. Diagnostic performance between preoperative FNAC and BRAF V600E mutation detection was compared between the two groups.

RESULTS

Pipette mixing substantially reduced the proportion of samples with undetectable BRAF V600E mutations, thereby increasing the yield of interpretable results (p < 0.05). In the non-mixed group, 12 samples fell below the detection limit, compared to only 2 in the mixed group. The proportion of TBSRTC Category III samples was lower in the mixed group (12/180) than in the non-mixed group (38/180, p < 0.05). Pipette-mixed FNAC combined with BRAF V600E testing improved preoperative diagnostic efficiency, particularly for thyroid nodules with indeterminate or non-diagnostic cytology.

CONCLUSIONS

Pipette mixing of FNAC samples improves the detection efficiency of BRAF V600E mutation and enhances diagnostic accuracy for thyroid nodules, especially in challenging cases. This simple technique may optimize preoperative diagnosis and guide clinical decision-making.