Massive pneumatic expansion of lymphatic vessel resulting in cystic lesions in the pulmonary parenchyma: a rare case of persistent interstitial pulmonary emphysema in a non-ventilated infant.

We report the case of 2-week-old female infant with cystic lung disease who presented with mild tachypnea and had no history of mechanical ventilation. Chest CT demonstrated multiple air-filled cystic lesions in right upper lobe, and the patient subsequently underwent a right upper lobectomy. Histology revealed cystic lesions located in the pulmonary parenchyma and showed that the lesions were lined by lymphatic endothelium and were communicating with dilated lymphatic vessels in the interstitium. Additionally, multinucleated foreign body giant cells were attached to the lumen of the cyst. On the basis of these findings, we considered this a case of persistent interstitial pulmonary emphysema (PIPE) with massive pneumatic expansion of the lymphatic vessels, resulting in cystic lesions with lymphatic endothelium in the pulmonary parenchyma. While PIPE is extremely rare in term non-ventilated infants, our case demonstrated that this disease should be added to the differential diagnosis of cystic lung diseases with lymphatic endothelium even in infants without mechanical ventilation. When cystic lesions and symptoms persist despite conservative treatment, open or thoracoscopic resection is an appropriate option for diagnosis and treatment.