[The intra-thyroid thyroglossal cyst in the differential diagnosis of the solitary thyroid nodule: A presentation of 2 cases].

Thyroglossal cysts are the most frequent neck malformation in children. They are usually located in the anterior midline near the hyoid bone, and may appear at the lingual (2.1%) or suprasternal (12.9%) level. Their presentation as a solitary thyroid nodule (STN) has been described in the literature and poses a challenge in the differential diagnosis of thyroid disorders in children. We present two cases that illustrate the clinical presentation and diagnostic test findings of this disease. The first patient was a boy 2 years of age presenting with a nodule in the right side of the neck, painless, well-defined, and adhered to the deep planes. Ultrasound examination showed a cystic nodule 8 mm × 11 mm × 17 mm in the thyroid. Iodine-131 scintigraphy showed a cold nodule and homogeneous uptake through the rest of the gland. The thyroid function tests were normal. Surgery was performed to reach a definitive diagnosis, revealing a cyst with mucinous contents in the upper right lobe of the gland compatible with thyroglossal duct cyst. The lesion was surgically resected and the histopathological study confirmed the diagnosis. The second case corresponded to a boy 10 years of age with a painless nodule in the medial edge of the sternocleidomastoid muscle. Ultrasound examination showed a cystic lesion in the right thyroid lobe measuring