A chylothorax (or chyle leak) is a type of pleural effusion. It results from lymphatic fluid (chyle) accumulating in the pleural cavity. Causes Its cause is usually leakage from the thoracic duct or one of the main lymphatic vessels that drain to it. The most common causes are lymphoma and trauma caused by thoracic surgery. If the patient is on a normal diet, the effusion can be identified by its white and milky appearance as it contains high levels of triglycerides. The condition is rare but s… (More on Chylothorax)