The value of frozen section examination in planning surgery for follicular thyroid neoplasms

Frozen section examination of follicular neoplasms of the thyroid has been claimed to be of little value in planning the extent of surgery. Clinical factors such as age, sex and tumour size are said to be more accurate predictors of malignancy. The aim of this study was to examine the respective value of clinical factors and frozen section in the surgical management of follicular thyroid neoplasms. A retrospective study of 735 patients with follicular neoplasms treated at Royal North Shore Hospital was undertaken. Factors assessed included clinical features, such as age and sex of the patients and tumour size, as well as findings at frozen section examination. No significant difference in sex distribution was demonstrated when comparing follicular adenoma with follicular carcinoma. There was a significant difference with respect to patient age between the two groups, but the large overlap in the distribution made this difference of no clinical value. In addition, there was no significant difference in tumour size when comparing follicular adenoma with carcinoma. On the other hand, review of frozen section results showed that 40% of patients with follicular carcinoma were positively identified by frozen section examination at initial surgery, with a false positive rate of less than 0.2%. It appears that clinical factors, such as age, sex and tumour size, are of little assistance in differentiating benign from malignant follicular neoplasms. Frozen section examination remains the most definitive tool in planning intra-operatively the extent of surgery for follicular neoplasms of the thyroid.