Giant mediastinal lymphangioma in a 4-year-old girl: a case report

Mediastinal lymphangiomas are rare benign congenital malformations of the lymphatic system in children, often presenting with non-specific respiratory symptoms and posing diagnostic challenges. A previously healthy 4-year-old female presented with progressive chest pain and intermittent dyspnea. Imaging revealed a large multiloculated cystic lesion (9.6 × 7.3 × 10.8 cm) occupying much of the right hemithorax, causing leftward mediastinal shift and compression of adjacent structures. Thoracentesis and right pigtail thoracostomy yielded partial drainage but incomplete resolution. Workup for Echinococcus , Histoplasma , Coccidioides , and tuberculosis was negative. Cyst fluid and blood cultures showed no growth, while cytology of the cyst fluid demonstrated inflammatory cells without evidence of malignancy. She was treated empirically with intravenous antibiotics for presumed obstructive pneumonia. On hospital day 8, she underwent right thoracotomy with complete excision of the multiloculated cystic mass, which was adherent to but separate from the pericardium and lung. There was no lymphatic leak, and the intraoperative chest tube was removed on postoperative day 2. Histopathology confirmed a benign cystic lymphangioma. The patient was discharged on hospital day 11 and remained asymptomatic and recurrence-free at 1-year follow-up. Mediastinal lymphangioma should be considered in the differential diagnosis of pediatric patients presenting with progressive respiratory symptoms or cystic mediastinal lesions on imaging.