ABSTRACT
A chylothorax and a cholesterol pleural eusion represent the two forms of lipid eusions encountered. Although these two eusions oen share a similar pleural uid appearance due to the high lipid concentration, there are dierences in the pathogenesis, clinical presentation, diagnosis, predisposing conditions, and management. A chylothorax is dened by the presence of chyle in the
pleural space resulting from obstruction or disruption of the thoracic duct or one its major tributaries. A triglyceride concentration >110 mg/dL is virtually diagnostic, and the presence of chylomicrons conrms the diagnosis. However, chylothorax dened by these criteria represents a heterogeneous group of clinical entities. In contrast, a cholesterol eusion is typically the result of long-standing pleurisy with elevated cholesterol levels in the pleural space; however, this paradigm has been challenged.
