Natural History and Outcomes of Cytologically Benign Thyroid Nodules in Children.

CONTEXT

Most pediatric thyroid nodules are cytologically benign, but few data exist to guide treatment.

OBJECTIVE

To describe the natural history and outcomes of cytologically benign, pediatric thyroid nodules.

DESIGN

Cohort study.

SETTING

Multidisciplinary thyroid clinic at an academic medical center.

PATIENTS

Consecutive pediatric patients (≤18 years old) with cytologically benign thyroid nodules evaluated between 1998 and 2016.

RESULTS

Cytologically benign nodules (N = 237) in 181 patients were followed by ultrasound (median follow-up, 3.4 years; range, 0.5 to 13.9 years) or to resection. Thyroid cancer was diagnosed in six nodules (2.5%), and all six patients were disease free after median follow-up of 4.9 years. Malignancy was more common in nodules >4 cm (15.4%; P = 0.037) or that grew during follow-up (6.0%; P = 0.048). The likelihood of nodule growth (±SE) was 15% ± 3%, 24% ± 4%, and 49% ± 10% at 6, 12, and 24 months, respectively. Among nodules >2 cm, those with ≥25% cystic content grew more slowly than nodules <25% cystic; nodules <2 cm grew similarly regardless of cystic content.

CONCLUSION

Benign cytology in pediatric thyroid nodules has a low false-negative rate similar to that in adults, and prognosis is excellent in the rare cases of malignancy. Resection of nodules >4 cm, combined with surveillance of smaller nodules and repeated aspiration for growth, detects most false-negative results. Follow-up ultrasound in 12 months is appropriate for most cytologically benign pediatric nodules, but delaying surveillance up to 24 months may be reasonable in large, predominantly cystic nodules.