Mesenteric lymph nodes seen at imaging: causes and significance.

With the advent of multidetector computed tomography, routine evaluation of mesenteric lymph nodes is now possible. For the first time, normal mesenteric nodes may be reliably identified noninvasively. Because of the increasing volume of cross-sectional imaging examinations being performed, lymph nodes in the mesentery are being detected with increasing frequency. This is often an unsuspected finding. Although the detected lymph nodes may be normal, there is a large number of disease processes that may lead to mesenteric lymphadenopathy. The most common causes of mesenteric lymphadenopathy are neoplastic, inflammatory, and infectious processes. Many of these causes may also result in lymphadenopathy elsewhere in the body. It is important to recognize mesenteric lymphadenopathy in patients with a history of a primary carcinoma because the lymphadenopathy affects the staging of the disease, which in turn will affect further management. In addition, mesenteric lymphadenopathy may be the only indicator of an underlying inflammatory or infectious process causing abdominal pain. The distribution of the lymph nodes may indicate the exact nature of the underlying disease process, and the correct treatment may then be instituted. Besides neoplastic, inflammatory, and infectious processes, many other disease processes may occasionally result in mesenteric lymphadenopathy. (c) RSNA, 2005.