Chylous ascites refers to an accumulation of triglyceride-rich fluid in the abdominal cavity occurring in the setting of disruption to the chyle-containing lymphatics. Lymphatic disruption can occur iatrogenically (post-surgical) or can be caused by trauma or obstruction resulting from increased lymphatic pressure due to congenital anomalies, inflammatory diseases, compressive malignancies, cirrhosis, pericarditis, or infections, namely tuberculosis, filariasis, or Mycobacterium avium-intracellulare infection.

Patients present with ascites, characterized by a buildup of fluid in the abdomen that can cause weight gain, abdominal pain, or dyspnea.

Chylous ascites in the Western world is most often iatrogenic or due to malignancy, cirrhosis, or congenital lymphatic anomalies. In the developing world, infection is the leading cause of chylous ascites. In pediatrics, congenital anomalies account for the majority of cases of chylous ascites.