The combined role of ultrasound and frozen section in surgical management of thyroid nodules read as suspicious for papillary thyroid carcinoma on fine needle aspiration biopsy: a retrospective study.

BACKGROUND: The purpose of this study was to evaluate the combined role of ultrasound (US) and frozen section (FS) in the surgical management of thyroid nodules that are suspicious for papillary thyroid carcinoma (PTC) on US-guided fine-needle aspiration biopsy (US-FNAB).

METHODS: Between 2006 and 2008, 217 patients with thyroid nodules classified as suspicious for PTC on US-FNAB underwent intraoperative FS and surgery. A thyroid nodule with any suspicious US findings of marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, or taller than wider in shape was defined as positive and that without was defined as negative. FSs were classified as malignant, indeterminate, defer, and benign. We compared the results of US groupings, FS, and final histopathologic diagnosis.

RESULTS: Twenty-one (52.5%) of 40 patients with a negative US revealed malignancy. In contrast, 168 (94.9%) of 177 patients with a positive US had malignancy. Fourteen (50%) of 28 patients with benign pathology on FS had malignancy, and 166 (97.6%) of 170 patients with malignancy on FS proved malignancy on histopathology. Of 40 patients with negative US, 13 (92.9%) of 14 with malignancy on FS proved malignancy.

CONCLUSIONS: The malignancy rate of thyroid nodules read as "suspicious for PTC" on US-FNAB was 87.1%. When a thyroid nodule with "suspicious for PTC" on US-FNAB has suspicious malignant US features, FS may be unnecessary due to a very high risk of malignancy (94.9%). In contrast, when a thyroid nodule read as "suspicious for PTC" on US-FNAB has no suspicious malignant US features, FS can help surgeons determine the extent of surgery.