Mesenteric lymphadenitis: This condition, often caused by viral or bacterial infections, is a common cause of mesenteric lymph node enlargement, especially in children and young adults. It can mimic appendicitis and is usually self-limiting.

Gastrointestinal infections: Infections such as salmonellosis, yersiniosis, or campylobacteriosis can cause mesenteric lymphadenitis.
Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can lead to mesenteric lymph node enlargement due to chronic inflammation.
Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can involve the mesenteric lymph nodes, though this is less common than other causes.

Abdominal lymphoma: Although less common, lymphoma involving the mesenteric nodes can be life-threatening if not diagnosed and treated promptly.
Tuberculosis: Though rare in many parts of the world, abdominal tuberculosis can cause mesenteric lymphadenitis and has significant implications for treatment and public health.
Sarcoidosis: This systemic disease can involve any organ, including the lymph nodes, and requires specific treatment.

Whipple's disease: A rare, systemic bacterial infection that can cause malabsorption and lymphadenopathy, including mesenteric lymph node enlargement.
Castleman disease: A rare disorder that involves an overgrowth of cells in the lymphatic system, which can lead to lymph node enlargement, including in the mesenteric region.
Kawasaki disease: Although primarily known for affecting children and causing coronary artery aneurysms, it can also involve lymphadenopathy, including mesenteric lymph nodes, in rare cases.