Bilateral Breast Uptake of 99mTc-Pertechnetate in a Neonate With Congenital Hypothyroidism

A 4-day-old female neonate with raised cord blood thyroid-stimulating hormone (127 μIU/mL) underwent Tc thyroid scan to rule out thyroid dysgenesis. The images revealed midline focus of lingual thyroid as the only functioning thyroid tissue. In addition, bilateral focal and symmetrical breast uptake was seen without clinically palpable breast nodule on either side. Transplacental transfer of maternal hormones leading to stimulation of neonatal breasts explains this unusual scan finding. One should be aware of this rare pattern of focal breast uptake in Tc-pertechnetate scan in neonates with congenital hypothyroidism to avoid scan misinterpretation.