CASE FOR DIAGNOSIS A baby with cough and poor feeding

A 9-week-old female baby presented at her local hospital with a 10-day history of cough and poor feeding. The pregnancy had been uneventful with normal antenatal scans. The baby was born at term by normal vaginal delivery weighing 3.23 kg with good American Paediatric Gross Assessment Record scores and was sent home on the second day after birth. Prior to this presentation, she had exhibited no respiratory symptoms and was maintaining good growth. On review, the baby was afebrile with no respiratory distress. Chest auscultation revealed reduced breath sounds on the left side. The rest of the physical examination results were unremarkable. Arterial oxygen saturation was 97% in air. Initial chest computed tomography (CT) results are shown in figure 1. Unfortunately, the initial chest radiograph was "lost". One week later, the baby underwent thoracotomy and resection. A chest radiograph taken the day prior to surgery is shown in figure 2. The histopathology of the lesion is shown in figure 3.