Israel Medical Association Journal

Background: Due to the high variability in malignancy rate among cytologically indeterminate thyroid nodules (Bethesda categories III–V), the American Thyroid Association recommends that each center define its own categorical cancer risk.

Objectives: To assess cancer risk in patients with cytologically indeterminate thyroid nodules who were operated at our center.

Methods: In a retrospective study, we analyzed the pathology results of all the patients whose fine needle aspiration results showed Bethesda III–V cytology and who subsequently underwent total thyroidectomy or lobectomy from December 2013 to September 2017.

Results: We analyzed 56 patients with indeterminate cytology on fine needle aspiration. Twenty-nine (52%) were defined as Bethesda III, 19 (34%) Bethesda IV, and 8 (14%) Bethesda V category. Malignancy rates were 38%, 58%, and 100% for Bethesda categories III, IV, and V, respectively. Most malignancies in Bethesda categories III and IV were follicular in origin (follicular thyroid carcinoma and follicular type papillary thyroid carcinoma), while 100% of the patients with Bethesda category V were diagnosed with classical papillary thyroid carcinoma. No correlation was found between sonographic and cytological criteria of nodules with Bethesda categories III and IV and rates of malignancy.

Conclusions: We found higher than expected rates of malignancy in indeterminate cytology. This finding reinforces the guidelines of the American Thyroid Association to establish local malignancy rates for thyroid nodules with indetermined cytology.

Background: Fine needle aspiration is the main diagnostic tool used to assess thyroid nodules.

Objectives: To correlate FNA[1] cytology results with surgical pathological findings in two teaching medical centers across the Atlantic.

Methods: We retrospectively identified 484 patients at Hadassah University Hospital, Jerusalem and Mount Sinai Hospital, New York, by means of both preoperative FNA cytology and a final histopathological report. Results compared FNA diagnosis, histological findings and frozen section results (Mt. Sinai only).

Results: The sensitivity value of FNA at Hadassah was 83.0% compared with 79.1% at Mt. Sinai (NS). Specificity values were 86.6 vs. 98.5% (P < 0.05), negative predictive value 78.7 vs. 77.6% (NS) and positive predictive value 89.7 vs. 98.6% (P < 0.05), respectively. "Follicular lesion" was diagnosed on FNA in 33.1% of the patients at Hadassah and in 21.5% at Mt Sinai (P < 0.005) with a malignancy rate of 42.5 vs. 23.1% (P < 0.05), respectively. Frozen section was used in 190 patients at Mt. Sinai (78.5%) with sensitivity and specificity values of 72.3% and 100%. Frozen section results altered the planned operative course in only 6 patients (2.5%). Follicular carcinoma was diagnosed in 12 patients at Hadassah vs. 2 patients at Mt. Sinai (P p <0.05).

Conclusion: The sensitivity of FNA at the two institutions was comparable. While malignancy on frozen section is highly specific, it should be used selectively for suspicious FNA results. Follicular lesions and the rate of malignancy in such lesions were more common at Hadassah, favoring a more aggressive surgical approach.