Thymic cysts in children: An unusual cause of upper airway obstruction

SummaryThe thymic cysts (TC) are rare, benign tumors of the neck and mediastinum. We reported a case of TC and discussed the physiopathology, differential diagnosis and treatment of this lesion. A 9-year-old male presented with a history of lateral neck swelling. Ultrasound revealed a cystic mass that was giving an impression of branchial cleft cyst. MRI demonstrated a multiloculated enhancing soft tissue lesion extending into the retropharyngeal space displacing the airway. The mass was completely excised. Histological evaluation of specimen revealed lymphoid cell populations and degenerated Hassall's corpuscles around cysts as a TC. TC are rare lesions that typically present as an asymptomatic cervical or mediastinal mass and are usually diagnosed after surgical extirpation. Complete surgical resection is the treatment of choice, but for the excellent prognosis with minimal morbidity, observation alone may be an option in asymptomatic patients.