Accuracy of fine needle aspiration and frozen section in the management of thyroid nodules

ABSTRACT

Aim: To determine the accuracy of fine needle aspiration [FNA] and frozen section [F.S.] in the management of thyroid nodules. The medical records of 85 patients who underwent thyroidectomy were retrospective l y analyzed. FNA and F.S. were performed on all patients and their results were compared with definitive histological assessment. Setting: Study was undertaken at the King Khalid University Hospital during the period from January 1996 to 1999. Among the 85 patients who were submitted for FNA cytology, 53 patients were diagnosed as benign, 13 patients as malignant and 19 were indeterminate. The incidence of malignancy in the indeterminate group was 19%. The diagnosis from the frozen sections was benign in 59 cases [68.8%], malignant in 13 cases and deferred in 13 cases. Diagnostic accuracy up to 98% was achieved when FNA cytology and frozen section diagnoses agreed. No false positives were observed when FNA cytology and F.S. were positive for malignancy. When FNA cytology and F.S. diagnoses were discordant, F.S. showed a higher accuracy [100%] than FNA cytology. In the face of an indeterminate cytological diagnosis, the diagnostic accuracy of F.S. reached 100% with exclusion of the deferred group. Conclusions: FNA is an accurate preoperative tool for the initial evaluation of thyroid nodules. F.S. is a valuable test for confirming the FNA results and is more accurate than FNA in cases of discordant diagnosis