Sudden death of a 14-year-old girl with lymphangiomatosis.

A 14-year-old girl presented with progressively worsening intermittent orthopnea. Imaging studies showed cardiomegaly, extensive pericardial effusion, and a mediastinal tumor. By pericardial drainage, approximately 8,000-mL fluid was collected over 10 days. Left thoracoscopic pericardial fenestration and mediastinal tumor biopsy were performed, revealing lymphangiomatosis. Chylous pleural effusion developed post-surgery. Although control was attempted, her condition worsened. Eight months later, she died of sudden cardiopulmonary arrest. Autopsy revealed systemic spread of the primary lesion from the hyperplastic lymph ducts to the parietal pleura and mediastinum confirming systemic lymphangiomatosis.