Fig. 4.

Histopathological findings. Microscopically, confluent non-caseating granulomas with extensive necrosis are seen in the lung parenchyma. The granulomas are of the sarcoid type, palisaded by Langerhans-type giant cells and mononuclear lymphohistiocytes with central necrosis. Another typical finding is the presence of vasculitis, usually granulomatous, and a large zone of necrosis. a) Large zone of necroris (×50); b) granulomatous vasculitis (×100); c) confluent granulomas and vasculitis (× 100).