Figure 2. Mycobacterium avium-intracellulare (MAI) and Mycobacterium tuberculosis (MTB) lymphadenopathy. (a) In this 36-year-old man with MAI infection, there are discrete lymph nodes of uniform attenuation within the retroperitoneum and small bowel mesentery. (b) In another 38-year-old man with MTB infection, lymph nodes within the retroperitoneum show typical central low attenuation.