An unusual enlarged thymus

Abstract

We describe the case of a 22-month-old boy attending a follow-up visit at our paediatric pulmonology outpatient clinic.At 30 weeks' gestational age, fetal ultrasonography had suggested malformation of the upper lobe of the left lung. He was born at term by caesarean section and physiologically adapted to extrauterine life. CT at birth showed extended dishomogeneous consolidation in the upper lobe of the left lung consistent with congenital cystic adenomatoid malformation (CCAM). Bronchoscopy and surgical resection 22 days later allowed the CCAM to be microscopically classifi ed as type II. Slow postoperative recovery of spontaneous breathing required 13 days' assisted ventilation. Upon discharge, chest radiography showed lightening of the previous opacity.The child remained asymptomatic and grew normally, but follow-up chest radiography (required about 2 years after surgery) showed renewed consolidation in the upper lobe of the left lung (fi gure 1A), and CT with contrast revealed an enlarged thymus fi lling the space of the lobe (fi gure 1B).CCAM is rare and usually diagnosed ultrasonographically before birth. 1 2 Elective surgery is required because of longterm risks, especially infection and malignancy. 3 Thymic hyperplasia (usually asymptomatic and less extended than in our case) is not rare in infancy but has never been described in association with CCAM. 4 5 In our case, the space left by surgical resection was replaced by an enlarged thymus gland mimicking CCAM recurrence or extensive lung atelectasia.

Asymmetric thymic hyperplasia following repair of congenital diaphragmatic hernia

“…It is likely that the asymmetry is noted postoperatively after the pressure from intrathoracic abdominal viscera herniation is relieved. This pattern has also been reported following a large neonatal lung resection 5. Providers should be aware of the anomalies associated with neural crest-derived organs, as well as the potential postoperative asymmetry.…”