Late development of mediastinal calcification in sarcoidosis.

Calcification of mediastinal lymph nodes developed in more than 20% of 111 patients with sarcoidosis followed for 10 yr or more. Lymph node calcification appeared in most instances during the second or third decade after the onset of the disease, chiefly in patients who had both mediastinal adenopathy and pulmonary infiltrates. Pre-existent calcification attributable to tuberculosis or histoplasmosis was noted in less than 3% of patients. As a result of the decline in mycobacterial infection, sarcoidosis may be the most common cause of calcified mediastinal and hilar lymph nodes appearing in patients after the age of 30.