Congenital pulmonary lymphangiectasis (CPL) is a rare vascular malformation causing dilated lymph vessels and disturbed drainage of lymph fluid. Based on the pathogenesis and clinical phenotype it can be classified as primary or secondary CPL.

Associated genetic syndromes with or without lymphedema, familial occurrence and gene mutations have been described. In utero, it may present as non-immune hydrops with pleural effusions. At birth neonates may have respiratory failure due to chylothorax and pulmonary hypoplasia, causing very high short term mortality rates. Other cases may become symptomatic any time later in childhood or even during adult life. CPL is usually diagnosed based on the combination of clinical signs, imaging and histological findings. Open-lung biopsy is considered the gold standard for the diagnosis of CPL. Treatment is primarily supportive featuring aggressive mechanical ventilation and the management of problems associated with congenital chylothorax including chest-drainage, medium-chain triglycerides (MCT) diet, and octreotide.