This patient had no history of tuberculosis infection. Primary infection is often asymptomatic, and it is discovered years later incidentally on x-ray done for other reasons (as in this case). The infection can be confirmed by a tuberculin skin test (also called Mantoux test).
In most cases, primary TB infection is localized, forming a caseating granuloma (tuberculoma), which eventually calcifies forming the Ghon lesion.
In some cases, hilar lymphadenopathy is present which also heals with calcification. When both are present the combination is called Ranke complex.