The incidence of cancer and rate of false-negative cytology in thyroid nodules greater than or equal to 4 cm in size.
BACKGROUND
High false-negative rates for fine needle aspiration biopsy (FNAB) of thyroid nodules greater than 3 cm have prompted recommendations for diagnostic lobectomy. We considered the presence of a greater than 4 cm nodule an independent indication for thyroidectomy regardless of FNAB results.


METHODS
We reviewed clinical data from 223 patients with thyroid nodules greater than or equal to 4 cm operated on from July 2003 to November 2006. Unifocal micropapillary cancer was considered clinically insignificant.


RESULTS
Clinically significant thyroid cancer was frequent, occurring in 57 of 223 patients (26%). Subgroup analysis showed that 43 of 223 patients (19.3%) had carcinoma within the mass and that 7 of 223 patients (3.1%) had significant carcinoma elsewhere in the resected thyroid. Multifocal micropapillary cancer was found in an additional 7 of 223 patients (3.1%). Preoperative FNAB was read incorrectly as benign in 9 of 71 patients with cancer (13%) (16% including multifocal micropapillary carcinoma). Benign FNAB results failed to identify 24 (34%) follicular lesions (including 7 cancers). In patients with preoperative FNAB results categorized as indeterminate lesions, 17 of 43 patients (40%) had carcinoma of the mass on final pathology.


CONCLUSIONS
In thyroid nodules greater than or equal to 4 cm, the incidence of carcinoma is high with a high false-negative rate for preoperative benign cytology. Thyroid nodules greater than or equal to 4 cm should be considered for diagnostic lobectomy regardless of FNAB results.
Department of Surgery, University of Pittsburgh, Pa., USA.
Kelly L
KL
McCoy
Noel
N
Jabbour
Jennifer B
JB
Ogilvie
N Paul
NP
Ohori
Sally E
SE
Carty
John H
JH
Yim
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000592:standards; D002291:Carcinoma, Papillary / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D016606:Thyroid Nodule / Q000453:epidemiology* / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy; D013967:Thyroiditis, Autoimmune / Q000453:epidemiology / Q000473:pathology / Q000601:surgery