Congenital multinodular goiter in a neonate presenting with airway obstruction

Introduction

Congenital neck masses are an unusual problem at birth, and the commonest types are thyroglossal duct and branchial apparatus abnormalities [1]. Congenital goiter contributes a minority of such cases and most of them are due to dyshormonogenesis [2]. Such goiters are almost always diffuse swellings and multinodularity has not been described. Here we report a baby with congenital multinodular goiter with hypothyroidism that presented with airway compression.

Case report

A 37 weeks’ gestation female neonate born to non-consanguineous parents with a normal perinatal transition presented to the pediatric emergency department on day 2 of life with neck swelling and noisy respiration since birth. The antenatal period was uncomplicated with normal antenatal ultrasonography (USG) at 6 and 9 months of gestation. The treating physician noticed a neck swelling and associated stridor at birth and referred the baby to our hospital for further management. There was no family history of goiter or iodine deficiency related illness and the family was consuming iodinated salt as part of their regular diet. The index subject weighed 3700 g at admission (at 90^th centile) with a crown-heel length of 51 cm and head circumference of 35 cm. Neck examination revealed an asymmetric, lobulated, firm, nonfluctuant, non-tender, swelling in the anterior aspect of the neck of size 3×3×5 cm on the right and 3×2×3 cm on the left side. The overlying skin was normal without any features of inflammation (Figure 1); no fixation to the skin or underlying bony structures; was non-trans illuminant and had no bruit on auscultation. Mild subcutaneous edema was noticed, however, without any evidence of fluid collection in any of the serous cavities. The edema became passive over the next 7 days. The systemic examination was normal. The baby did not have any features of hypo- or hyperthyroidism.

Figure 1:

Neck swelling at presentation, with the corresponding CECT scan showing multinodular thyroid swelling (arrows) [3].

A neck ultrasonography (USG) failed to delineate the anatomical origin of the swelling and the subsequent contrast enhanced computerized tomography (CECT) scan of the neck showed a multi-nodular swelling possibly arising from the thyroid gland (Figure 1). A fine needle aspiration cytology (FNAC) examination showed benign thyroid follicular cells with scanty colloid and no lymphocytic infiltration. Thyroid function tests (TFT) are presented in Table 1. Technetium (Tc 99) and iodine (I 123) scans, performed on day 8 of life, were suggestive of enlarged thyroid gland, with an increased trapping function (a 2-h iodide uptake of 23.8%). The baby was started on levothyroxine 50 μg per day (on day 7 of life) following which the swelling decreased markedly over the next 3 weeks and stridor became passive. The dose of oral thyroxine was titrated according to the serial TFTs. The neurological examination and developmental assessment of the baby done at 18 months of life was normal.

Discussion

Congenital goiter is an infrequent cause of neck masses and congenital hypothyroidism in neonates [3, 4]. A hypothyroid goiter presenting at birth is usually secondary to dyshormonogenesis. Transient hypothyroidism secondary to maternal antithyroid drugs intake, transplacental passage of antibodies, maternal and neonatal iodine deficiency or excess and hepatic hemangioma hemangioendothelioma have a similar presentation. In the index subject, the TFTs of the mother, father and sibling were normal, there was no history of antithyroid drug intake during pregnancy and USG of the abdomen was normal. An increased uptake in the radionucleotide scan ruled out uptake defects such as Na-I symporter defects. A low TG value and thyroid follicular cells in FNAC with scanty colloid were strongly suggestive of thyroglobulin synthetic defects [5]. A confirmatory molecular analysis could not be done in the index case.

Early diagnosis and effective replacement therapy of congenital hypothyroidism is associated with a better neuro-developmental outcome. The index case was started on 13 μg/kg/day of L-thyroxine, and this was followed by normalization of T4 and TSH and regression of swelling within 2 weeks of start of therapy. Selva et al. suggested that a higher dose (12–17 μg/kg/day) may be required in those with very low T4 values at birth [6]. Thyroglobulin synthetic defects are rare causes of dyshormonogenetic hypothyroidism [7]. Generally subjects with these defects have scanty colloid synthesis and a milder sized goiter and very few case reports of thyroglobulin synthetic defects have been reported to have presented with a large neck mass. Similarly, multinodularity due to long standing multiplication, fibrosis and hemorrhagic necrosis of a few clones of follicular cells [8] is extremely rare in a congenital goiter.

Conclusion

This case report demonstrates a possible rare defect in thyroglobulin synthesis with an unusual presentation as a neck mass large enough to cause airway obstruction. This case is also unique to present as a congenital multi-nodular goiter and further demonstrates the dramatic effect of early diagnosis and timely institution of replacement therapy on the hormone function as well as the size of the swelling.