Abstract

TORRES, Maria; MARTINS, Hugo  and  LOUREIRO, Aluízio. Hyperthyroidism caused by lingual thyroid tissue in a child with congenital hypothyroidism. Nascer e Crescer [online]. 2017, vol.26, n.3, pp.185-187. ISSN 0872-0754.

Ectopic thyroid is an anomaly in the migration of the thyroid between the third and seventh week of gestation. Most of patients remain asymptomatic, hyperthyroidism is very unusual. The authors found only three cases reported to date. We report the case of a girl diagnosed with congenital hypothyroidism at birth, being since then medicated with levothyroxine. When she was 21-year-old, a routine blood test revealed a TSH level of 0.00 mU/L and therefore the hormone treatment was suspended since there was suspicion of iatrogenic hyperthyroidism, which was later excluded. Neither the thyroid ultrasound nor the thyroid scintigraphy showed thyroid tissue on-site, so a full body scintigraphy was performed which showed toxic ectopic lingual thyroid tissue. The treatment was started with metimazol 15 mg a day. When a «new» hyperthyroidism is observed after a congenital hypothyroidism had been diagnosed, ectopic lingual thyroid must be suspected.

Keywords : Congenitalhypothyroidism; ectopichyperthyroidism; lingual thyroid.

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