Chylous Ascites

A 69-year-old man with HCV cirrhosis and newly diagnosed diffuse large B cell lymphoma was admitted for chemotherapy. He had a distended abdomen and an abdominal ultrasound revealed ascites.

Paracentesis yielded 2 l of pink, milky-appearing ascitic fluid that separated into two layers, with a white layer on top (Fig. 1). Ascitic fluid triglycerides were 330 mg/dl.

Figure 1

Milky-appearing ascitic fluid immendiately following paracentesis (left), and several hours later separating into two distinct layers (right).

The diagnosis of chylous ascites should be suspected when ascitic fluid appears milky and is established when the ascitic fluid triglyceride level is > 200 mg/dl.^{1, 2} In developing countries, infection is the most common cause, including tuberculosis and filariasis.¹ In developed countries, the most common causes are abdominal malignancy and cirrhosis with lymphoma being responsible for approximately 8% of cases in adults.^{1, 3} The mechanism of action of chylous ascites due to lymphoma is obstruction of lymphatic drainage secondary to lymphadenopathy, causing exudation of chyle.⁴ This patient’s significant retroperitoneal lymphadenopathy visualized on PET/CT (Fig. 2) likely caused obstruction of the cisterna chyli that receives lymphatic drainage in the abdomen.

Figure 2

PET/CT coronal section demonstrating enlarged retroperitoneal lymph nodes (fused arrows).

The mainstay of management of chylous ascites is treatment of the underlying condition. This patient received chemotherapy with R-CHOP for treatment of his lymphoma. A low-fat diet with medium-chain triglyceride supplementation is also generally recommended.^{5, 6}