[Basic differentiation of granulomatosis and fibrosis in sarcoidosis (author's transl)]

Active pulmonary granulomatosis due to sarcoidosis in stage I is characterized on chest films by well-defined enlarged hilar and mediastinal lymph nodes. In stage II a involved lymph nodes decrease in size. Interstitial infiltration causes ill-defined broadening of vessels and bronchi. Focal infiltrates correspond to just detectable or nodular lung shadows of up to several centimeters in size. Active granulomatosis is demonstrated by Gallium-67-scans in lymph nodes as well as in areas of interstitial and focal pulmonary infiltrates. Following spontaneous or therapeutically induced regression of granulomatosis the abnormal uptake is not seen anymore. X-ray findings of fibrosis include partial shrinkage of pulmonary lobes or segments along with displacement of vessels and bronchi and (fibrous) adhesions of interlobar, parietal and mediastinal pleura. Honeycombed, occasionally bullous emphysema are the most reliable findings suggesting fibrosis. In addition to the fibrosis demonstrated on chest films, the Gallium-67-scan often shows progressive granulomatosis. So stage III disease is often (almost regularly) associated with stage II disease. Such cases still need further treatment.