A newborn with neck mass.

Congenital goiter is a rare cause of neonatal neck mass and may result from a fetal defectin synthesis of thyroxine, or administration of antithyroid drugs or iodides during pregnancy. The thyroid dysfunction often accompanies it. This report describes a case of a male term newborn with congenital goiter and primary hypothyroidism. Hormonal replacement treatment was started leading to normal levels of free thyroxine and triiodothyronine. In face of a maternal negative investigation, dyshormonogenesis was considered to be the most probable cause of hypothyroidism.