“Suspicious” Thyroid Cytologic Findings: Outcome in Patients Without Immediate Surgical Treatment

From January 1980 through December 1988, 8,219 thyroid smears were obtained by fine-needle aspiration (FNA) biopsy from patients at the Mayo Clinic, of which 918 (11%) were classified as “suspicious” cytologic findings. We analyzed the outcome in 208 patients with such findings who did not undergo immediate surgical treatment at the Mayo Clinic; follow-up data on thyroid status were available for 187 patients. Of 99 patients who underwent late surgical treatment (more than 30 days after FNA biopsy) and for whom tissue was available for diagnosis, thyroid malignant disease was found in 29. No clinical, scintigraphic, or ultrasonographic characteristics predicted the presence of a malignant lesion. On repeated FNA biopsy in 41 patients, findings were suspicious for a malignant lesion in 19 and benign in 22. Surgical excision was performed in 13 of the 41 patients. For 11 patients with suspicious cytologic findings on two FNA biopsies, malignant disease was confirmed in 5 and benign disease in 6. Two patients had benign histopathologic findings after cytologic results were benign on a second FNA biopsy. Follow-up data for the 208 patients revealed that 86 were alive with no evidence of thyroid disease, 76 were alive with some evidence of thyroid disease, 23 had died of nonthyroid illnesses, 2 had died of a thyroid malignant lesion, and 6 had died without undergoing surgical treatment (thyroid status unknown at the time of death); follow-up information was unavailable in 15 patients. The median duration of follow-up for those alive was 4.9 years. Our findings support the current practice of recommending immediate or late surgical treatment for all patients with suspicious thyroid cytologic results. Because repeated FNA biopsy adds little information, it is not recommended.