Duplicated thyroglossal duct cyst with intrathyroidal involvement in a paediatric patient

Thyroglossal duct cysts are the most common congenital cervical lesions in childhood. Intrathyroidal location and duplication or bifurcation of the duct are exceptionally rare variants.

An 11-year-old boy presented with two cervical masses: one subcutaneous lesion in the left infrahyoid region and another deep lesion in the right thyroid lobe. Ultrasonography and magnetic resonance imaging identified a 2 × 2 cm intrathyroidal cyst and a 3 × 3 cm subcutaneous lesion, findings consistent with a duplicated thyroglossal duct cyst with intrathyroidal involvement. A Sistrunk procedure was performed, with en bloc excision of both lesions. Histopathological examination confirmed ductal duplication, with one branch extending into the thyroid gland.

This case highlights the importance of advanced imaging in atypical or recurrent cervical lesions and emphasises the need to consider uncommon embryological variants of the thyroglossal duct.