Pseudochylothorax: An unusual mode of revelation of pleural metastasis from solid tumor

Pseudochylothorax is a rare cause of pleural effusion. Sometimes confounded with chylothorax, firm diagnosis relies on analysis of the pleural liquid: exudative liquid (protein >30 g/L, lactate dehydrogenase >200 UI/L) with a high level of cholesterol (usually >200 mg/dL), low level of triglyceride (usually <110 mg/dL), cholesterol total/triglyceride ratio >1, absence of chylomicron, and in some cases the presence of cholesterol crystals. Pseudochylothorax is secondary to tuberculosis and rheumatoid arthritis in nearly 90% of cases. Its oncologic etiologies are mainly represented by malignant hematologic disorders.