Endoscopic Ultrasound With Bronchoscope-Guided Fine-Needle Aspiration (EUS-B-FNA) in a six-Month-Old Infant: A Case Based Review of Literature.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is an established, minimally invasive modality for evaluating mediastinal pathologies in adults. However, its application in infants remains extremely limited because of airway size constraints and procedural safety concerns. We report the case of a 6-month-old infant presenting with recurrent lower respiratory tract infections and a posterior mediastinal lesion causing bronchial compression. Contrast-enhanced computed tomography demonstrated a well-defined cystic lesion in the right posterior mediastinum, with differential diagnoses including bronchogenic cyst, duplication cyst and necrotic lymphadenopathy. Given diagnostic uncertainty and the risks of primary surgical intervention, EUS-B-FNA was performed via transoesophageal approach under general anaesthesia. Cytological analysis revealed cyst macrophages and acellular mucoid debris, confirming a bronchogenic cyst. The patient subsequently underwent definitive surgical excision and remained symptom-free on follow-up. This case represents the youngest reported infant to undergo successful mediastinal sampling using EUS-B-FNA and highlights the feasibility, safety and diagnostic utility of the transoesophageal bronchoscopic ultrasound approach in very young children when performed in experienced centres.