Case 13-2021: A Newborn Girl with a Neck Mass

A newborn girl presented with a large neck mass detected prenatally at 34 weeks of gestation. Postnatal imaging and laboratory evaluations initially suggested a sympathetic chain lesion, possibly neuroblastoma. However, pathological examination revealed a follicular thyroid neoplasm with hyperplastic features. Genetic testing identified a somatic NRAS mutation (G61R), confirming a rare congenital thyroid neoplasm. The case highlights diagnostic challenges in differentiating neonatal neck masses and the importance of multidisciplinary evaluation. The infant underwent surgical excision, with normalization of thyroid function postoperatively and successful tracheostomy decannulation at 14 months.

A newborn girl presented with a large neck mass detected prenatally at 34 weeks of gestation. Postnatal imaging and laboratory evaluations initially suggested a sympathetic chain lesion, possibly neuroblastoma. However, pathological examination revealed a follicular thyroid neoplasm with hyperplastic features. Genetic testing identified a somatic NRAS mutation (G61R), confirming a rare congenital thyroid neoplasm. The case highlights diagnostic challenges in differentiating neonatal neck masses and the importance of multidisciplinary evaluation. The infant underwent surgical excision, with normalization of thyroid function postoperatively and successful tracheostomy decannulation at 14 months.