Abstract
BACKGROUND: Unilateral pulmonary agenesis is a rare congenital anomaly with an incidence of 1:15,000, affecting both sides and sexes equally. It's classified by Schneider-Schwalbe (Types 1–3) and Boyden systems (Groups 1–3) based on developmental severity. Children commonly experience recurrent respiratory tract infections and breathing difficulties due to aberrant tracheal function and increased vulnerability from airway constriction. CASE PRESENTATION: A 9-year-old male presented with fever and nonproductive cough. Physical examination revealed severe malnutrition (weight and BMI < -3Z score) with tracheal deviation, decreased left chest movement, dullness to percussion, and diminished breath sounds on the left side. Chest X-ray showed complete left hemithorax opacification with mediastinal shift. High-resolution computed tomography revealed left lung aplasia with compensatory right lung hyperinflation. Computed tomography pulmonary angiogram (CTPA) confirmed left pulmonary artery agenesis. Bronchoscopy demonstrated hypoplastic left bronchial tree with blind-ending left main bronchus and tracheal bronchus supplying the right upper lobe. The patient was treated with antibiotics for secondary infection, chest physiotherapy, inhaled corticosteroids, and nutritional support. CONCLUSION: This rare congenital anomaly highlights the importance of advanced imaging in diagnosing complex respiratory presentations in pediatric patients with recurrent respiratory infections. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-025-06487-7.