Glándula tiroides lingual: diagnóstico y tratamiento / Lingual thyroid gland: diagnosis and treatment

La presencia de glándula tiroidea ectópica es una entidad rara. La tiroides lingual es la ectopía mas frecuente, predominando en mujeres. Este tejido glandular es pasible de sufrir todas las patologías que pueden afectar a la glándula normotópica, pudiendo ser sintomática o asintomática. Se presenta un caso de tiroides lingual en una paciente previamente tiroidectomizada que consultó por disnea y disfagia en la unidad de Cirugía de Cabeza y Cuello del Servicio de Otorrinolaringología del Hospital Central del Instituto de Previsión Social, Asunción, Paraguay. La paciente recibía tratamiento hormonal de reemplazo,mostrando examen funcional normal. La semiología permitió observar un abombamiento de la base de la lengua. La fibroscopía mostró un tumor en base de lengua de unos 3 cm de diámetro, que pudo evaluarse correctamente con una tomografía computada. Ante la sospecha de una tiroides lingual se realizó un centellograma que demostró captación en piso de cavidad oral. Se realizó excéresis tumoral a través de una faringotomía suprahioidea, previa traqueostomía proofiláctica. El informe de Anatomía Patológica confirmó el diagnóstico de bocio coloide ectópico.

The presence of ectopic thyroid gland is a rare entity. The lingual thyroid is the most frequent ectopy, predominating in women. This glandular tissue is capable of suffering all the pathologies that can affect the normotopic gland, being able to be symptomatic or asymptomatic. We present a case of lingual thyroid in a previously thyroidectomized patient who consulted for dyspnea and dysphagia in the Head and Neck Surgery Unit of the Otolaryngology Service of the Central Hospital of the Institute of Social Prevision, Asuncion, Paraguay. The patient received hormone replacement therapy, showing normal functional examination. Semiology allowed to observe a bulging of the base of the tongue. The fibroscopy showed atongue-based tumor about 3 cm in diameter, which could be correctly evaluated with computed tomography.Suspicion of a lingual thyroid was performed with a scintigram demonstrating uptake in the oral cavity floor.Tumor excision was performed through a suprahyoid pharyngotomy, following a prophylactic tracheostomy.The Pathologic Anatomy report confirmed the diagnosis of ectopic colloid goitre.

Resistance to thyroid hormone in a patient with thyroid dysgenesis.

We report a patient with the unusual coincidence of two rare congenital disorders, lingual ectopy of the thyroid gland and resistance to thyroid hormone (RTH), resulting in impaired thyroid hormone production and action, respectively. The proposita had a positive thyrotropin (TSH) newborn screening test (350 mU/L, confirmed) with normal thyroxine (T4) and no clinical signs of hypothyroidism. A scintiscan revealed lingual but no orthotopic thyroid tissue. Levothyroxine (LT4) replacement failed to reduce TSH and was discontinued after four months owing to significantly elevated free T4. Her physical and mental development was unremarkable, and she was considered to be clinically euthyroid throughout childhood, even though she received either no T4 or a dose insufficient to lessen hyperthyrotropinemia. At the age of 15 years, T4 was gradually increased to a supraphysiological dose of 300 microg/d, resulting in the normalization of the serum TSH level, and subjective improvements in her ability to concentrate. The proposita's mother was clinically euthyroid, had a palpable diffuse goiter, and thyroid function tests consistent with RTH. This diagnosis was confirmed by detection of a heterozygous mutation (R320H) in the thyroid hormone receptor-beta (TR-beta) gene found in both the proposita and her mother. Under the high-dose T4 regimen, the patient's TSH and free T4 values resembled those of untreated patients with TRbeta R320H mutation, suggesting that a compensated state could be achieved, at least at the pituitary level. In the proposita, treatment of hyperthyrotropinemia is clearly mandatory because of potential complications inflicted by TSH-stimulated growth of the lingual tissue. To our knowledge, this represents the first report of congenital hypothyroidism secondary to thyroid dysgenesis complicated by coincidental RTH.