Allergic bronchopulmonary aspergillosis. A, Mucoid impaction of bronchi. A dilated bronchus is filled with lamellated, eosinophilic debris. B, Same case as A. The intrabronchial debris is composed of necrotic eosinophils and mucus. Note characteristic Charcot-Leyden crystals (arrow). Branching hyphae are present within the debris (inset). C, Same case as A, showing bronchocentric granulomatosis. Necrotizing granulomatous inflammation (arrows) destroying a bronchiole (arrowhead). Note the necrotic debris filling the bronchiolar lumen. D, Same case as A showing a bronchocentric necrotizing granuloma at high magnification. Palisading histiocytes at bottom left, necrosis rich in eosinophils at top right (hematoxylin-eosin, original magnifications ×20 [A], ×400 [B], ×40 [C], ×200 [D]; Grocott methenamine silver, original magnification ×400 [B, inset]).