A 25-year-old woman presented to our 
hospital with a 1-week history of cough and 
shortness of breath. A chest radiograph showed a 
left-sided pleural effusion that contained chyle. The 
findings of other examinations suggested no distinct 
disease. We made the diagnosis of idiopathic 
chylothorax and operated only on the left side 
because magnetic resonance thoracic ductography 
depicted the thoracic duct on the left side. The 
intraoperative finding was chylous effusion flowing 
through a pleural fistula over a cystic lesion. We 
resected the lesion and ligated the thoracic duct in a 
left thoracotomy. The histopathologic diagnosis was 
Lymph Angioleio Myomatosis (LAM), which 
recurred after the operation. Sirolimus was given 
along with redo ligation of thoracic duct, resulting 
in cessation of chylothorax. A preoperative 
evaluation on possible LAM might have prevented 
the recurrence in combination with sirolimus.