Thyroid teratoma in an infant: a case report

Background Thyroid teratoma is an exceptionally rare germ cell tumor in the pediatric population, accounting for less than 1% of childhood teratomas. Despite its rarity, it may cause life-threatening airway compression, particularly in neonates and infants. Case Presentation We report the case of an 8-month-old infant who presented with a progressively enlarging, painless anterior neck mass measuring approximately 6 cm in its largest diameter, associated with dysphagia. The infant had been followed by a pediatric endocrinologist since the age of 2 months, when the TSH level was initially elevated but subsequently normalized spontaneously. Neck ultrasonography revealed a well-circumscribed, heterogeneous mass with both solid and cystic components, originating from the thyroid gland and displacing adjacent cervical structures without evidence of local invasion. Serum alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (β-hCG) levels were within normal limits. The patient underwent complete surgical excision of the tumor through a cervical approach, including resection of the right thyroid lobe, which had been completely replaced by the mass. Histopathological examination confirmed the diagnosis of a mixed mature and immature thyroid teratoma. The surgical margins were free of tumor. The postoperative course was uneventful. At 42 months of follow-up, the child remained asymptomatic, with hypothyroidism managed with medication and no evidence of local recurrence. Conclusion Teratoma must be included in the differential diagnosis of cervical masses in infants.