Does frozen section have a role in the intraoperative management of thyroid nodules?

Frozen section in thyroid surgery is used to make an intraoperative pathological diagnosis of malignancy in a thyroid nodule at the time of hemithyroidectomy. A positive diagnosis allows completion of thyroidectomy, thus avoiding reoperation. However, the use of fine needle aspiration cytology in making a preoperative diagnosis of cancer has resulted in the lack of a defined role for frozen section. We examined the role of frozen section as an adjunct to fine needle aspiration cytology in determining which cytological subset will benefit from frozen section.

All patients who underwent thyroidectomy between 1992 and 2000 by a single endocrine surgeon were reviewed.

Two hundred and nine frozen sections were performed, of which 144 underwent preoperative fine needle aspiration cytology. Frozen sections reported 135 benign nodules, 59 follicular neoplasms, five specimens with suspicious histology and 10 cancers. Ten out of 20 thyroid cancers were correctly identified by frozen section (sensitivity: 50%; specificity: 100%), eight cancers were reported on frozen section as indeterminate and two benign. Of 144 fine needle aspiration cytological procedures, frozen section on seven suspicious aspirates identified two cancers, and frozen section on 70 follicular aspirates identified four cancers, allowing intraoperative conversions to total thyroidectomy. Frozen section on seven malignant aspirates confirmed four cancers but resulted in reoperation for three because of the indeterminate frozen section reports. There were no cancers found on 135 benign aspirates.

Frozen section on benign aspirates is unhelpful in the management of thyroid nodules. It need not be performed for cytologically proven malignant thyroid nodules. Selective use of frozen section complements fine needle aspiration cytology findings of suspicious or follicular lesions, especially in the subset with papillary cancer, allowing one-stage total thyroidectomy.