Congenital pulmonary airway malformation: a case report and review of the literature.

Congenital parenchymal lung malformations have an estimated incidence at 1:25,000-1:35,000 births. We present a case of this rare congenital abnormality in a 38 year-old male, review the current literature with discussion of proposed causes, malignant potential, and management strategies. A 38-year-old white male presented with a 4-day history of chronic stable hemoptysis. Social history was notable for a 50-pack-year active smoking history and remote heavy alcohol consumption. Physical examination was normal. Chest radiograph revealed an ill defined right lower lobe infiltrate. Chest computed tomography demonstrated an irregular, thin-walled, cystic lesion with adjacent nodularity and calcifications. The patient received a right lower lobectomy. Pathologic specimen demonstrated a 10-cm, mostly thin-walled cyst with features suggestive of a congenital cyst adenomatoid malformation and areas of adenocarcinoma (mixed subtype with acinar and bronchioloalveolar patterns). Congenital cyst adenomatoid malformations have recently been renamed as congenital pulmonary airway malformations and are the most common type of congenital parenchymal lung malformations. Individuals typically present with recurrent pulmonary infections, pneumothorax, or hemoptysis. The development is controversial but believed to be a result of arrested development of the fetal bronchial tree during the sixth and seventh week of fetal development. Defects in thyroid transcription factor 1 have also been proposed. With the increasing use and image resolution of ultrasound in modern obstetric practice, congenital pulmonary airway malformations rarely go undetected into adulthood. Management remains controversial; however, most authors agree with early surgical excision.