Aim: To determine diagnostic relevance of cytologic subclassification of follicular lesions of the thyroid and its role in the therapeutic approach.
Methods: We performed a retrospective analysis of the data of patients who underwent thyroid surgery at the Sisters of Mercy University Hospital, Zagreb, between March 1995 and February 2001, and had a report of preoperative fine needle aspiration (FNA) biopsy of thyroid follicular lesion, which comprises cellular follicular lesion, suspicious for follicular neoplasm, or follicular neoplasm.
Results: Out of 110 patients with preoperative FNA biopsy diagnosis of follicular lesion, 86 (78%) had a lesion corresponding histologically to a neoplasm. However, a malignant tumor was found in only 6% of the patients. In the diagnostic categories of cellular follicular lesion and lesion suspicious for follicular neoplasm, the rate of malignancy was even lower, 3% and 4%, respectively. We found significant difference between FNA and histologic findings in distinguishing non-neoplastic from neoplastic thyroid lesions in the category of cellular follicular lesion and follicular neoplasm.
Conclusion: Due to the low malignancy rate in patients with FNA biopsy diagnoses of cellular follicular lesion or lesion suspicious for follicular neoplasm of the thyroid, we suggest close clinical follow-up of such patients, rather than immediate surgical intervention.