RESUMO
White thyroid scintigraphy corresponds to an absence or near-absence of radiotracer fixation in the cervical region. After eliminating technical causes, the main etiologies are iodine overload, thyroiditis, and congenital hypothyroidism. We report the case of a 22-day-old newborn with congenital hypothyroidism. As part of the etiological assessment, a cervical ultrasound was performed and showed a normal echostructured thyroid gland with no detectable lesions or vascular anomalies. On the other hand, a Tc 99m thyroid scintigraphy was also performed and revealed a lack of radiotracer uptake in the thyroid area in favor of a white thyroid scintigraphy. Congenital hypothyroidism is the main cause of mental retardation. Thyroid scintigraphy plays an important role in the etiological diagnosis of congenital hypothyroidism. A white thyroid scan and a thyroid in place on cervical ultrasound point to iodine transporter deficiency caused by sodium/iodide symporter gene mutations.