Factors that predict malignant thyroid lesions when fine-needle aspiration is "suspicious for follicular neoplasm"

To assess clinical factors that may improve the ability to predict the presence of a malignant lesion in thyroid nodules that are found to be "suspicious for follicular neoplasm" by fine-needle aspiration (FNA) cytology.

We undertook a retrospective review of the medical records of all patients at the three Mayo Clinic facilities who underwent a thyroid surgical procedure between January 1992 and December 1994 and had a preoperative FNA report of "suspicious for follicular neoplasm." Patient and nodule characteristics were analyzed statistically for associations with the presence of cancer.

The study cohort consisted of 219 patients with a mean age of 54.3 years. Eighty-four percent of resections were done for benign disease. Of the 35 malignant lesions, 9 were incidental papillary cancers separate from the primary nodule; thus, only 26 cancers were found in the index nodule, and only 19 (9% of the total group) were follicular carcinomas. Clinical findings associated with a malignant index nodule were larger diameter, fixation of the mass, and younger age of the patient.

Clinical characteristics may be used for more accurate assessment of the risk of the presence of a malignant lesion when FNA cytology of a thyroid nodule is reported as "suspicious for follicular neoplasm."