Same as it happens with the lungs, swollen lymph nodes may affect abdominal organs as well and even disturb the natural return of blood to the heart. In this case, a condition called ascites ensues, in which there is free liquid in the abdominal cavity caused by exudate of serum into the interstitial tissue.
In some cases, enlarged lymph nodes start affecting the normal function of the liver, which results in a swollen abdomen, a yellowish coloration of the skin called jaundice, bloating, and other symptoms. It is common to have a swollen spleen as well, and this organ can become really large and even reach your belly button in some cases.
All of these symptoms are very unspecific and do not point out to immune dysfunction, which is why they should be evaluated along with others to suspect lymphoma or rule out other common diseases.