Aim: We aimed to investigate the value of frozen section examination that patients with nodular goitre whose diagnosis were benign preoperatively, but suspicion existed in operative theatre.

Materials and method: Seventy-six patients with multinodular goitre whose diagnosis were PAP Class II preoperatively and in whom frozen section was performed because of malignancy suspicion, such as firm, fixed nodul with calcification or found lymph node at the operation, were included study. Patients' ages, gender, results of frozen section, type of operations, and histopathologic findings were recorded. Results of frozen section and histopathologic findings were compared. Frozen section specifity and sensitivity were calculated.

Results: Sixty-seven of 76 patients (88.1 %) had benign, 9 of 76 (11.9 %) patients had malign thyroideal disease. All 5 patients whose frozen section diagnosis were malign, histopathologic findings were also malign. Four of 71 patients (5.6 %) whose frozen section diagnosis were benign, were found malign in histopathologic examination. Sensitivity and specifity of the frozen section were found 55.5% and 100% respectively, in discrimination of the malign thyroideal disease.

Conclusion: In Pap Class II thyroid lesions, if there is some suspicion about malignancy at operation, frozen section investigation is strongly suggested. We conclude that frozen section's specifity is high and can be used safely.