Chylothorax is the presence of lymphatic fluid in the pleural space caused by a leak of the thoracic duct or one of its divisions. Causative factors include congenital abnormalities, trauma, surgery, and neoplastic processes. Tumour-related chylothorax can occur by direct invasion and erosion of the thoracic duct by the primary tumour or a tumour embolus, or by an indirect effect of back pressure and rupture of distended tributaries. Radiotherapy can cause narrowing of lymph vessels and consequent impaired lymph flow, but this mechanism is rarely described as a cause of chylothorax. 1 McWilliams A Gabbay E Chylothorax occurring 23 years post irradiation: literature review and management strategies. Respirology. 2000; 5: 301-303 Crossref PubMed Scopus (25) Google Scholar , 2 Zoetmulder F Rutgers E Baas P Thoracoscopic ligation of a thoracic duct leakage. Chest. 1994; 106: 1233-1234 Summary Full Text Full Text PDF PubMed Scopus (39) Google Scholar , 3 Lee YC Tribe AE Chylothorax from radiation induced mediastinal fibrosis. Aust NZ J Med. 1998; 28: 667-668 Crossref PubMed Scopus (7) Google Scholar