The only way to know the diagnosis for certain is to obtain a tissue biopsy. As you already know, the mesenteric lymph nodes are located in the abdomen, near the intestine. Enlargement could have one of several causes, including viral or bacterial infections, parasites or lymphoma. If the nodes can be easily accessed surgically and there are no other medical reasons to avoid surgery, it may be reasonable to try to get a tissue sample for examination. It’s somewhat difficult to make specific recommendations in your case without seeing the CT scans. It may also be useful to perform a CT scan of your chest to see if there are any other areas that might be more easily accessed for biopsy. If the nodes are small and you have no symptoms, continued close observation may also be a reasonable alternative. Q2. I have swollen lymph nodes on the right side of my neck. What causes this? Lymph nodes help your body fight infection by producing lymph, a fluid that travels throughout your body and filters impurities such as bacteria and abnormal cells. There are a number of reasons why a lymph node may become swollen, including infection, inflammation and lymphoma. Infection is the most common. Illnesses that can cause swollen lymph nodes include mononucleosis, ear infections, tonsillitis, skin infection due to an ingrown hair, or even an impacted tooth. If there is evidence of an infection, it may resolve within a week or two, or a course of antibiotics might be prescribed for you, followed by close evaluation. Depending on the size and location of the lymph nodes, and whether they get larger or resolve, you may need a biopsy to fully determine the cause of the swelling. Q3. Recently, I discovered by a PET scan that my lymph nodes were inflamed. I was diagnosed with MS in 1982 and in 2004 was prescribed Betaseron (interferon beta 1-b) by my neurologist. My immune system has also been affected since 2004. What type of doctor can help me now? I am very concerned about the inflamed lymph nodes. The first step is to have a biopsy of one of the lymph nodes. Not all enlarged lymph nodes, even when they are positive on PET scan, represent lymphoma. In addition, there are many different types of lymphoma. Typically, a surgeon will do a biopsy if your lymph nodes can be felt on physical exam. If not, what is called a core needle biopsy can sometimes be done under the guidance of a CT scan, if a node is in an accessible location. If a lymph node can not be sampled in this way, patients sometimes require an open surgical procedure to make a diagnosis. Your neurologist should be able to recommend the proper physician in your area. Q4. My dad died of non-Hodgkin’s lymphoma on Dec. 19, 1994 at the age of 77. He was told in 1992 that he had about six months left, so my sister and I both made trips home that Thanksgiving as it might be his last one. He actually lived another two years. How curable are the various forms of lymphoma? I heard that if Hodgkin’s is detected early enough, it can be rather easy to cure, but the non-Hodgkin’s that my dad had is very difficult to cure, if at all, no matter how early it’s detected. What is the story about this, please? There are many different types of non-Hodgkin’s lymphoma, and the prognosis depends on the specific diagnosis. Prognosis can also vary within the same subtype. Even in a patient who has a well-defined subtype of lymphoma, the length of survival can be difficult to predict. For patients with fast-growing lymphomas (such as diffuse large B-cell lymphoma), the disease can be cured with combination chemotherapy. For patients who do not respond to treatment or have early relapses, however, the disease can be fatal in a relatively short amount of time. The slow-growing lymphomas are not curable with standard chemotherapy, but patients may live with them for many years. Learn more in the Everyday Health Lymphoma Center.