Figure 3: Representative histologic appearance of the lungs in a reactivating guinea pig. The pulmonary parenchyma was effaced by multifocal and coalescing granulomas that were usually associated with airways; foci of mineralization consistent with those in Figure 2 were also observed [A]. In many areas reduplication of airway epithelium was prominent and some large airways contained numerous degenerate neutrophils and macrophages [B]. Inflammation was predominantly histiocytic with epithelioid macrophages, rare multinucleated giant cells and lymphocytes. Central necrosis was observed within some lesions [C]. Size bars 500 µm [B] and 50 µm [C].