# Unusual congenital goiter due to maternal Hashimoto thyroiditis: a case report

## TL;DR

A newborn developed a rare congenital goiter due to high levels of maternal thyroid antibodies from Hashimoto thyroiditis.

## Contribution

This case report highlights a rare instance of congenital goiter caused by maternal Hashimoto thyroiditis and high TPOAb levels.

## Key findings

- A male newborn presented with grade 3 goiter and hypothyroidism due to maternal Hashimoto thyroiditis.
- Levothyroxine treatment normalized thyroid function in the newborn.
- Neurological development remained normal following treatment.

## Abstract

Congenital hypothyroidism (CH) is the most common cause of endocrinopathy in the newborn Its incidence lies between 1 in 3,000 and 1 in 2,000, However, congenital goiter is a rare form of presentation. Hypothyroidism secondary to autoimmune etiology is extremely rare, with an incidence of 1:84.700–1:31.000 newborns. Anti-thyroid peroxidase antibodies (TPOAb) are able to cross the placenta but rarely induce hypothyroidism in the newborn, much less goiter. A case of congenital goiter in a male newborn secondary to maternal high TPOAb levels is reported. The mother was diagnosed of Hashimoto thyroiditis prior to the pregnancy. At birth, a grade 3 goiter was detected in the newborn. Laboratory testings revealed hypothyroidism with free thyroxine of 7.6 pmol/L, thyroid-stimulating hormone of 108 mUI/L and high TPOAb levels. Treatment with Levothyroxine was started the second day of life with progressive thyroid function normalization. Neurological development has been normal until the date.