An unusual case of biphasic stridor in an infant: Suprasternal bronchogenic cyst

Abstract

Bronchogenic cysts are congenital lesions resulting from aberrant budding of the embryonic foregut. Although they may occur at any point along the tracheobronchial tree, symptomatic suprasternal bronchogenic cysts are extremely rare. A 7-month-old male was referred to the Otolaryngology– Head and Neck Surgery service with a presumptive diagnosis of laryngomalacia based on a 5-month history of progressive stridor, dysphagia, and poor weight gain. The stridor was biphasic, low-pitched, and associated with moderate tracheal tugging. A round mass was seen to prolapse above the suprasternal notch and left clavicular head during neck extension and crying. Flexible endoscopic laryngoscopy was unremarkable. A chest x-ray revealed a widened mediastinum with significant tracheal deviation to the right (Figure 1; available at www.jpeds.com). A computed tomography (CT) scan demonstrated a large homogeneous cystic lesion originating from the posterior mediastinum (Figure 2). A 4.0 5.0 cm fluid-filled cyst was excised from the lateral wall of the mid-trachea through a partial median sternotomy with cervical extension (Figure 3). Histopathology revealed a cyst lined by pseudostratified ciliated columnar epithelium with irregular fascicles of smooth muscle, focal islands of hyaline cartilage, scattered seromucinous glands, and fibrovascular stroma (Figure 4; available at www.jpeds.com). These features were consistent with a diagnosis of bronchogenic cyst. A history of progressive stridor, dysphagia, and failure to thrive is of concern and warrants an immediate airway investigation. The biphasic nature of the stridor indicated a fixed airway obstruction. This must be differentiated from laryngomalacia, which is associated with an inspiratory, highpitched stridor. CT scans are diagnostic in more than half of the cases, but magnetic resonance imaging may be required to elucidate the cystic nature of the lesion. 1 Surgical excision is the definitive treatment to alleviate the airway obstruction and prevent possible infection and acute airway obstruction. 2 The prognosis is excellent with surgical excision.