Improved preoperative definitive diagnosis of papillary thyroid carcinoma in FNAs prepared with both ThinPrep and conventional smears compared with FNAs prepared with ThinPrep alone

BACKGROUND:

ThinPrep (TP) liquid‐based preparations are increasingly being used in nongynecologic specimens. Few studies have evaluated TP as a sole diagnostic modality in the setting of thyroid fine‐needle aspiration (T‐FNA). Herein, the authors evaluate the usefulness of TP as a sole diagnostic modality in a nonsplit sample.

METHODS:

Consecutive T‐FNAs were identified at 2 tertiary care institutions; 1 institution processed thyroid FNA entirely with TP, and the other used a combination of TP and conventional preparations (CP). Cytodiagnoses, surgical pathology, and/or clinical follow‐up were recorded. Performance parameters for the 2 settings were compared.

RESULTS:

A cytologic diagnosis of positive for malignancy was correct in 98.8% of TP + CP cases and in 100% of TP cases. Papillary thyroid carcinoma cases were definitively diagnosed in 53.1% of T‐FNAs prepared by TP + CP compared with 34.4% of T‐FNAs prepared with TP alone (P = .0015 by Fisher 2‐tailed exact test). Of patients ultimately diagnosed with papillary thyroid carcinoma, 89% were initially treated by total thyroidectomy in the TP + CP group compared with 79.5% in the TP‐only group (P = .027 by Fisher exact test).

CONCLUSIONS:

TP as a sole preparatory technique does not improve the usefulness of T‐FNA as a screening test. However, combining CP and TP increases the rate of definitive cytologic diagnosis of malignancy in papillary thyroid carcinoma. Thus, combining TP and CP enhances the diagnostic component of T‐FNA. Cancer (Cancer Cytopathol) 2011. © 2010 American Cancer Society.