Autonomous Functioning Thyroid Nodule - A Rare Paediatric Diagnosis

Autonomous functioning thyroid nodules may be defined as nodules in which follicular cells have a TSH independent function. Although not uncommon in adults, they are rare in patients younger than 18 years of age. Presenting features may be a visibly growing anterior cervical mass, symptoms related to airway or esophageal compression, or even hyperthyroidism-related symptoms. Diagnosis is made through thyroid function assessments and confirmed through a thyroid scintigraphy. We present the case of a teenage patient that presented with an anterior progressively growing cervical mass that, on initial assessment, had a normal thyroid function. On follow up, TSH suppression was detected, and the suspicion of an Autonomous Functioning Thyroid Nodule was later confirmed through I131 scintigraphy. The patient underwent surgical resection, and has since, remained euthyroid. Although rare, AFTN should be part of the differential diagnosis for thyroid nodules in the pediatric population, even if initial thyroid function assessments are normal.