Fine-needle aspiration biopsy specimen with a predominance of Hürthle cells: a dilemma in the management of nodular thyroid disease.

BACKGROUND: A fine-needle aspiration biopsy (FNAB) specimen of a thyroid nodule with a predominance of Hürthle cells usually is indicative of a Hürthle cell neoplasm, but it also may occur with nonneoplastic disease.
METHODS: A prospective nodular thyroid disease database was used to identify patients with a FNAB specimen consisting of a predominance of Hürthle cells. Clinical factors were investigated and FNAB specimens were examined in a blinded fashion by a single cytopathologist to determine if there were specific factors that could be used to distinguish nonneoplastic from neoplastic disease.
RESULTS: Of the 738 patients with nodular thyroid disease, 622 had a FNAB specimen. The FNAB specimen was interpreted as consistent with a Hürthle cell neoplasm in 45 (7%) patients, 7 (16%) with carcinoma, 21 (47%) with adenoma, 12 (27%) with adenomatous hyperplasia, and 5 (11%) with thyroiditis. Extensive cellularity and absent colloid were associated with neoplastic disease (P < .05). No cytologic feature reliably excluded neoplastic disease (P > .05). No significant differences in age (x +/- SD) (51 +/- 17 vs 54 +/- 17 y), sex (female/male ratio, 6/1 vs 15/2), nodule size (3.9 +/- 1.9 vs 3.4 +/- 2.0 cm), weight of excised thyroid tissue (42 +/- 27 vs 33 +/- 30 g), or functional status of the thyroid gland was observed between patients with neoplastic (n = 28, 62%) versus nonneoplastic (n = 17, 38%) disease.
CONCLUSIONS: Neoplastic disease accounts for two thirds of the pathology in patients with a predominance of Hürthle cells on FNAB specimen and neither clinical nor cytologic features reliably exclude Hürthle cell adenoma or carcinoma. As a result, thyroidectomy is recommended for all patients with a thyroid nodule and a predominance of Hürthle cells on FNAB specimen.