CASE 11436 Published on 23.12.2013

Fetal goitre - MRI utility


Paediatric radiology

Case Type

Clinical Cases


Sofia Pina, Pedro Soares Pinto, Joao Teixeira, Maria Céu Rodrigues, Valentina Ribeiro

Centro Hospitalar do Porto,
Porto, Portugal

27 years, female

Area of Interest Foetal imaging ; Imaging Technique Ultrasound-Colour Doppler, MR
Clinical History
27-year-old primigravida, previously healthy and euthyroid. Routine fetal ultrasound at 29 weeks’ gestation reveals a fetal bilobed anterior neck mass. Sequential fetal MR was performed and thyroid hormones levels were studied by amniocentesis. Intraamniotic l-thyroxine was administered twice. Caesarean delivery at 39 weeks’ gestation, without immediate complications.
Imaging Findings
29 weeks transabdominal ultrasound (Fig. 1): fetal bilobed anterior neck mass measuring 4cm of maximal width, presenting low-flow vascularization, causing reduction in airway diameter, at the level of orohypopharyngeal transition.
29 weeks fetal MRI (Fig. 2): axial, coronal and sagittal T1 SS TFE, sagittal T2 SS TSE: bilobed anterior neck mass, well circumscribed, homogeneously hypointense on T2-weighted imaging and hyperintense on T1-weighted imaging, consistent with goitre (blue arrows). The mass remains with 4 cm of maximal width, surrounds and reduces the tracheoesophageal pathway, which is hyperintense on T2 (green arrow), reflecting the presence of amniotic fluid within it, a sign of normal flow. There is no polyhydramnios. Brain and spinal cord are normal.
36 weeks fetal MRI (Fig. 3): axial and coronal T1 3D SPGR fat sat, coronal T2 SS TSE and T2 Thick Slab. Findings are stable. No airway compromise (green arrow). No polyhydramnios.
Fetal goitre is an enlargement of thyroid gland in utero that may be noticed late in the first trimester after the fetal thyroid begins to function. It may occur with either hyperthyroidism, euthyroidism, or hypothyroidism. Hyperthyroid state is characterized by fetal tachycardia and advanced bone maturity; hypothyroid goitre by delayed bone maturation. If the mother is euthyroid the diagnosis of a fetal goitre is hard to establish on clinical grounds. [1]
A major concern regarding fetal goitre is the high risk of labour complications, frequently due to airway obstruction. The mass effect may also cause fixed hyperextension requiring a caesarean delivery. Polyhydramnios occurs from impaired swallowing, and is an indicator of airway obstruction, which should prompt an MR study. An MR performed closer to due date (third trimester) will better predict peripartum anatomy and will reduce the risk of complications during labour, avoiding consequent hypoxic–ischemic injury or even death. [1, 2]

Antenatal imaging detecting a goitre is important to prompt fetal thyroid function evaluation in order to initiate early treatment and for proper planning of labour. [1, 2]
In a fetal ultrasound it is possible to recognize a homogenous anterior fetal neck mass, hypervascular on colour Doppler study (peripheral vascularization is typical for hypothyroidism) [3]. The mass, usually symmetric, may also develop asymmetric. [4]
MR imaging features help to confirm the diagnosis of goitre, as the mass is typically homogenously hyperintense on T1, allows the evaluation of the mass (goitre volume), and adjacent structures, such as the tracheoesophageal pathway (patency is revealed by the hyperintense signal on T2-weighted images), and also the position of the neck, thus playing a pivotal role in planning the labour and perinatal management. [1, 2]
Fetal MR is an important diagnostic method, complementary to ultrasound, in confirming fetal goitre and excluding other neck masses, reducing perinatal complications and directing clinicians toward optimal management. [1, 2]

Enlarging goitres with polyhydramnios, compression of the trachea and possible asphyxia may be treated with intra-amniotic thyroxine or early delivery.
Fetal thyroid status may be determined by cordocentesis or amniocentesis (which is less invasive). Monitoring of thyroid levels in conjunction with goitre volume is very important to adjust l-thyroxine dosage for intraamniotic injections. Ideally the child should be euthyroid at birth. [5]
In this case, taking into account the maternal euthyroidism, congenital hypothyroidism with goitre is likely attributed to dyshormonogenesis. [6] The newborn developed, soon after birth, a severe hypothyroidism and moderate cardiac failure, with good response to l-thyroxine. Thyroid function and hormonal studies remained normal on follow-up studies.
Differential Diagnosis List
Fetal goitre, congenital hypothyroidism
Ectopic thymus
Final Diagnosis
Fetal goitre, congenital hypothyroidism
Case information
DOI: 10.1594/EURORAD/CASE.11436
ISSN: 1563-4086