Figure 12c. (a) Reticulonodular pattern in blastomycosis. Radiograph shows bilateral reticulonodular opacities, with a large cavitary lesion in the right upper lobe. (b) Magnified view more clearly depicts the interstitial opacities in the right lower lung. (c) On a CT scan, the reticulonodular opacities seen in a have a tree-in-bud appearance.