Utility of frozen-section examination for diagnosis of malignancy associated with multinodular goiter

Frozen-section examination (FSE) has traditionally been used for the intraoperative diagnosis of thyroid cancer. However, the utility of the technique is now controversial, especially in multinodular goiter (MNG), on which there are few studies. The aim of this study was to analyze the utility of FSE for ruling out malignancy in patients undergoing surgery for MNG.

FSE was performed in 197 patients with MNGs undergoing surgery for suspected malignancy, either preoperatively (n = 145; 74%) or intraoperatively (n = 52; 26%), and where the preoperatively planned surgical technique was partial resectional surgery. The FSE diagnosis was classified as benign, suggestive of malignancy, or malignant. The following FSE parameters were calculated for diagnosing MNG-associated carcinoma: true- and false-positives and true- and false-negatives, sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy. The chi2 and Student's t tests were applied.

The FSE revealed benignity in 191 cases (97%), suggested malignancy in 3 (1.5%), and were malignant in the remaining 3. The final histology revealed 16 carcinomas (8%), of which only 3 were detected by FSE. Only tumor size was a factor significantly associated with FSE carcinoma detection (p = 0.0012). The sensitivity of the technique for detecting carcinoma was 19%, specificity, 100%; positive predictive value, 100%; negative predictive value, 93%; and diagnostic accuracy, 93%.

FSE should not be used routinely in the management of MNG, and considering its low rate of sensitivity for detecting malignancy, the decision on the extent of the thyroidectomy should be based on other factors and explorations.