Clinicopathologic management of tumors of the thyroid gland in an endemic goiter area. Combined use of preoperative fine needle aspiration biopsy and intraoperative frozen section

In total, 15,325 fine needle aspiration (FNA) biopsies of the thyroid were examined in the Department of Pathology of the University of Innsbruck, Austria, between 1976 and 1985, with the cytologic results histologically verified in 3,112 cases. Since (1) it is frequently impossible to distinguish benign from malignant encapsulated follicular thyroid tumors by cytologic criteria and (2) there is a high level of follicular thyroid carcinoma in our endemic goiter area, we have adopted a diagnostic strategy that accepts a high percentage of false-positive cytologic results in order not to miss highly differentiated follicular carcinoma. To avoid unnecessarily extensive surgical treatment, 1,079 intraoperative frozen section examinations of the thyroid were performed in the same time period in (1) patients with preoperative suspicious or positive FNA cytologic findings, (2) cases with suspicious clinical and anamnestic data and (3) tumors with a suspicious macroscopic appearance without preoperative FNA or with negative or unsatisfactory cytologic findings. In 48 cases (4.5%), the frozen section diagnosis had to be revised after examination of paraffin-embedded tissue. An intraoperative false-positive diagnosis was obtained in 3 cases (0.3%) while a false-negative diagnosis was made in 45 cases (4.2%). The main effort in examining frozen sections should be concentrated on avoiding false-positive errors, which can lead to unnecessary thyroidectomies.