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Updated: Jul 7, 2026

An Orthotopic Mouse Model of Anaplastic Thyroid Carcinoma
Published on: April 17, 2013
Tumor size predicts malignant potential in Hürthle cell neoplasms of the thyroid
Rebecca S Sippel1, Dina M Elaraj, Elham Khanafshar
1Department of Surgery, University of California San Francisco and the UCSF Comprehensive Cancer Center at Mount Zion, San Francisco, CA 94143, USA. sippel@surgery.wisc.edu
Background:
A fine needle aspiration (FNA) diagnosis of a Hürthle cell neoplasm is associated with a 20% risk of malignancy. We sought to determine if the primary tumor size correlated with the risk of malignancy in patients with a preoperative FNA diagnosis of a Hürthle cell neoplasm.
Methods:
Between January 2000 and November 2006, 57 patients underwent a thyroidectomy with a preoperative FNA diagnosis of a Hürthle cell neoplasm. Patient histories, FNA reports, operative notes, and pathology reports were retrospectively reviewed. Statistical analysis was performed.
Results:
The overall rate of malignancy in patients with Hürthle cell neoplasms was 21%. The average tumor size was 3.2 cm, with malignant tumors being significantly larger than benign tumors (5.0 vs. 2.7 cm, p<0.01). The risk of malignancy directly correlated with tumor size. No malignancies were seen in tumors 2 cm or smaller (0/15). The risk of malignancy was only 13% (6/46) in tumors 4 cm or smaller and increased to 55% (6/11) in tumors larger than 4 cm. All tumors larger than 6 cm were malignant (4/4).
Conclusions:
Tumor size correlates directly with malignant potential in patients with Hürthle cell neoplasms of the thyroid. Among our patients, malignancy was not present in any tumors 2 cm or smaller and was present in all tumors larger than 6 cm. Because the risk of malignancy is greater than 50% in patients with a tumor larger than 4 cm, consideration should be given for an initial total thyroidectomy in these patients.

