Mycobacterium tuberculosis dissemination means that the human body is infected with Mycobacterium tuberculosis and disseminates this germ to other parts of the body through the bloodstream and lymphatic system. Mycobacterium tuberculosis can be spread through the lymphatic and blood systems after a primary focus of infection has formed in the lungs. This bacterium has a preference for spreading to organs with the richest blood supply, such as the liver, spleen, bone marrow, and brain. These distant lesions are often encased in granulomas that take weeks to months to heal; each lesion contains live microorganisms. Failure of these foci to heal early after the primary infection can lead to progressive primary disease at these sites. Reactivation of latent TB foci may occur, followed by invasion of adjacent lymphatics or blood vessels, leading to dissemination of viable microorganisms, resulting in granulomatous TB. Reactivation can occur at any time after primary infection, usually years or decades later. The major determinants of TB dissemination include virulence factors of the mycobacteria and the host’s immune defenses. It is recommended that the diagnosis of TB be followed by aggressive and standardized treatment to prevent life-threatening TB dissemination.