Purpose or Case Report: Congenital focal lung malformations (CLM) are a heterogeneous group of lesions that have been commonly classified by their features and the presence of systemic vascular supply into bronchial atresia, congenital pulmonary airway malformation, bronchogenic cyst and bronchopulmonary sequestration, however, pathologically there is considerable overlap not recognized by this classification method. Literature has hypothesized that a common pathogenetic origin of developmental bronchial obstruction, variable in timing and extent, is responsible for the spectrum observed.

The purpose of this case report is to describe the findings of an unusual CLM with concurrent intra and extrapulmonary lesions demonstrated by pre and postnatal imaging, gross and microscopic pathology.

A 19 year-old G1P0 female presented at 34 weeks gestation for evaluation of a fetal chest mass, first identified by US at 32 weeks. Fetal US showed a large right thoracic lung lesion containing two distinct macro cysts; fetal MR demonstrated T2 hyperintense signal throughout the lesion and increased volume of the affected lung with resultant mild mediastinal shift. No systemic feeding vessel was evident.

The baby was born at 39 weeks and required intubation due to respiratory distress. Postnatal CTA showed a solid lesion right thoracic apex outlined by pleural air with systemic arterial supply from the subclavian artery, no visible airways, and a central cyst with peripheral atelectasis. There was an additional unilocular cyst with air-fluid level in the perihilar right middle lung.

Thoracotomy on day 4 described an extrapulmonary sequestration (EPS) right thoracic apex and cystic lesions in the right upper and middle lobes, all of which were resected without complication. Pathology revealed similar histology throughout all resected tissue characterized by markedly dilated proximal bronchi and parenchymal maldevelopment with immature alveolar spaces as is seen in bronchial atresia, in addition to diffuse pulmonary interstitial glycogenosis.

This case of a CLM with concurrent solid and cystic lesions supports a common pathogenetic mechanism based on developmental bronchial obstruction both with and without retention of embryonic systemic vascular communication. Prenatal classification into distinct lesions is hampered by overlapping pathological features. Characterization of vascular and airway connections and awareness of potential complications are most important to guide counseling and therapy.
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