Case HistoryA full term male infant was delivered via normal spontaneous vaginal delivery (NSVD) to a 35 year-old G6P6006 mother with good prenatal care. Maternal antenatal laboratory results were normal. A maternal prenatal sonogram at 20 weeks gestation showed a solid echogenic mass in the left hemithorax ( Figure 1). A second ultrasound confirmed the initial findings, and showed a solid echogenic mass of 2.7 × 3.9 cm in size ( Figure 2). The mother received a Penicillin prophylaxis for positive Group B streptococcus colonization. The infant's Apgar score was 9/9 at 1/5 minutes respectively.The infant weighed 3070 g at birth and physical examination was appropriate for its age, with no abnormality detected. The infant remained clinically stable on room air without developing respiratory distress. The infant's chest rotengogram (CxR) was normal ( Figure 3). The computerized tomogram (CT) of the infant's chest showed a well demarcated, consolidated mass in the left lower lobe which had a solid and a cystic component, suggesting a diagnosis of a congenital pulmonary adenomatoid malformation (CPAM) or a bronchopulmonary sequestration (BPS) of the lung (Figure 4). A Doppler ultrasound of the left lung showed a solid mass, with no feed vessel thereby suggesting BPS as a likely diagnosis ( Figure 5). The baby remained asymptomatic and was discharged home to the parents with scheduled follow up appointments with a pulmonologist and a general pediatrician. The parents were also educated about the infant's clinical condition.The infant did well post-natally with normal growth and development. The infant underwent a thoracoscopic lobectomy of the left lower lobe (LLL) of the lung at 6 months of age. The final diagnosis was intra-lobar sequestration. The infant has been doing well since surgery and no complications were reported.
DiscussionCongenital fetal parenchymal lung malformations are uncommon but well documented lung abnormalities. The incidence of such abnormalities is 1 in 10,000 to 35,000 live births, with congenital pulmonary adenomatoid malformation (CPAM) and bronchopulmonary sequestration (BPS) being the most common. These are also the most common lung abnormalities that are diagnosed on prenatal ultrasound [1]. With the improvement in imaging techniques over the past decade, the diagnosis and management of lung abnormalities has completely changed [2].The exact pathophysiology of congenital lung abnormalities is unclear, but CPAMs are characterized by localized abnormal growth of lower respiratory structures during the pseudo-glandular period of fetal development (7 to 17 weeks) [3]. They are characterized by a cystic or solid intrapulmonary mass, usually unilobar with a slight predilection for the lower lobes that is usually diagnosed on routine antenatal ultrasound performed around 18 to 20 weeks of gestation [1]. They receive their blood supply from the pulmonary circulation. By contrast, BPS could manifest as an intra-lobar or extra-lobar malformation which may derive its blood supply from the ascendin...