Subglottic ectopic thymus mimicking airway haemangioma

Area of Science:

• Pediatric Otolaryngology
• Pediatric Pathology

Background:

• Subglottic hemangioma is a common cause of neonatal and infantile airway obstruction, typically diagnosed via endoscopy.
• Propranolol is the established first-line treatment for subglottic hemangioma.

Observation:

• A rare case of ectopic thymus presenting as a subglottic mass in an infant is described.
• The lesion initially responded to propranolol, mimicking hemangioma, but later showed progressive stridor refractory to treatment.

Findings:

• Histopathological examination after surgical excision confirmed the lesion to be ectopic thymus tissue, not hemangioma.
• Confirmation bias occurred due to the initial apparent response to propranolol.

Implications:

• Ectopic thymus is a critical differential diagnosis for subglottic masses in infants.
• Surgical excision should be considered for subglottic lesions refractory to medical management to ensure correct diagnosis.