Follicular Thyroid Carcinoma Presenting with A Hyperfunctioning Nodule in An Adolescent Girl

Background: Follicular thyroid carcinoma is rare in young patients and further diagnostic challenge is added when it presents as a hyperfunctioning thyroid nodule. Case report: We described a 14-year-old girl who presented with thyrotoxicosis and a large goitre associated with compressive symptoms. Thyroid scintigraphy demonstrated a solitary autonomous hyperfunctioning thyroid nodule. FNAC examination was not suggestive of malignancy. Thyrotoxicosis was controlled with carbimazole and a hemithyroidectomy was done. Histopathological examination revealed minimally invasive follicular thyroid carcinoma, following then, complete thyroidectomy was done. Discussion: This patient’s risk factors of malignancy were her age (young), gender (female), large nodule size, progressive growth, and compressive symptoms.  This case illustrates the limitation of FNAC to ascertain malignancy in patients with large AFTN as the initial FNAC report was consistent with a benign lesion. Surgical resection without prior FNAC should be considered for cases with hyperfunctioning thyroid nodule which then would allow timely histologic analysis and accurate diagnosis. Conclusion: Autonomous functioning nodules in children and adolescents warrant careful evaluation to exclude malignancy. Our case illustrated the challenges to discriminate between malignant and benign lesions preoperatively for children and adolescents who present with AFNT.