SHBC1008

B.W.W.LEE¹, M.B.MANISH², R.TAN¹, E.W.Z.FU², A.S.CHEW², J.WONG², C.SIEW², B.LIM², R.DALAN², M.Y.LIM², J.Y.GAN²,  LH²

MOH Holdings Pte Ltd (MOHH)¹, Tan Tock Seng Hospital²

The impact of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) on the risk of malignancy (ROM) in thyroid fine-needle aspiration cytology (FNAC) per The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has not been well studied in Singapore.

We retrospectively identified 821 thyroid nodules with preoperative FNAC from 788 patients out of 1279 consecutive thyroidectomies performed between January 2010 and August 2016 in a tertiary general hospital in Singapore. Possible cases of NIFTP were reviewed for reclassification and the impact of NIFTP on ROM was analysed.

The incidence of NIFTP was 1.2% (10 out of 821). ROM per Bethesda I to VI if NIFTP were benign was 8.6%, 3.5%, 26.2%, 21.4%, 87.7%, 97.0%, versus 8.6%, 4.2%, 28.4%, 21.4%, 89.2%, 100% if NIFTP were malignant. Eight patients with NIFTP had follow-up between 11 to 102 months. None developed recurrence or distant metastasis.

Classifying NIFTP as benign decreased ROM in Bethesda II, III, V and VI, but the impact of NIFTP on ROM appears to be lower than that reported in the Western studies.