Ectopic thymus presenting as neck mass in a neonate: a case report

Area of Science:

• Pediatric Surgery
• Histopathology
• Neonatal Care

Background:

• Neck masses in newborns are uncommon but pose diagnostic and surgical challenges.
• While most neck masses are benign, accurate diagnosis is crucial for appropriate management.
• Ectopic cervical thymus is a rare congenital anomaly presenting as a neck mass.

Observation:

• A two-month-old infant presented with a slowly enlarging, asymptomatic left-sided cervical mass noted since birth.
• Magnetic resonance imaging revealed a encapsulated solid mass lateral to the sternocleidomastoid muscle, without involving major neck vessels.
• Surgical excision was performed for definitive histological diagnosis.

Findings:

• Histological examination confirmed the mass to be ectopic cervical thymus tissue.
• This entity is rare, with only 91 cases reported, and exceptionally uncommon in infants (nine cases).
• The specific case involved an infant with a neonatal presentation.

Implications:

• Complete surgical resection is the definitive and safe procedure for enlarging solid neck masses with unclear imaging or clinical data.
• This case highlights the importance of considering rare diagnoses like ectopic cervical thymus in pediatric neck masses.
• Early diagnosis and surgical intervention are key for favorable outcomes in neonates with cervical masses.