Intrathoracic lymphadenopathy in postprimary tuberculosis.

In the past, hilar or mediastinal lymphadenopathy was considered by many to be a feature of only the primary or first infection with Mycobacterium tuberculosis, and to exclude the diagnosis of reactivation or postprimary tuberculosis. In a series of 56 adult patients with documented postprimary disease due to M tuberculosis, we found hilar or mediastinal lymphadenopathy in three cases (5%). Although intrathoracic lymphadenopathy was more common in primary tuberculosis, we do not believe that intrathoracic lymphadenopathy is as specific for primary tuberculosis, particularly in the adult, as was once thought. For this reason, we believe that the roentgenographic demonstration of intrathoracic lymphadenopathy should not be used as a definitive research or clinical criterion for primary tuberculosis in an adult.