Horseshoe lung associated with scimitar syndrome: the first reported case from Indonesia

Background Horseshoe lung is a rare congenital anomaly characterized by fusion of the posterior basal segments of both lungs across the midline, often associated with right lung hypoplasia and partial anomalous pulmonary venous return (PAPVR) as part of Scimitar syndrome. Case presentation We report a case of a 21-day-old male neonate presenting with persistent respiratory distress and a missed early diagnosis of horseshoe lung. Initial imaging revealed right lung atelectasis and PAPVR, leading to a diagnosis of Scimitar syndrome with atrial septal defect (ASD). At two months, bronchoscopy demonstrated laryngomalacia, right upper lobe agenesis, and right main bronchus stenosis. At age five, contrast-enhanced chest CT revealed a horseshoe lung with right lung hypoplasia, abnormal pulmonary venous drainage, and a tracheal bronchus. The patient underwent staged surgical correction between the ages of five and seven, achieving full recovery. At eight years old, he remained asymptomatic with normal growth. Conclusions This case underscores the importance of considering associated cardiopulmonary anomalies when evaluating neonatal respiratory distress. Early use of contrast-enhanced multidetector CT allows accurate delineation of pulmonary and vascular anatomy, facilitating prompt diagnosis and optimal surgical planning. This is the first documented Indonesian case of horseshoe lung with Scimitar syndrome, ASD, and tracheal bronchus.