hyphae invasion in sinus cavity mucosa of rat with acute invasive fungal rhinosinusitis (AIFR). Bone resorption is caused by the intrusion of hyphal masses. The hyphae are antler-like. (A1. Hematoxylin and eosin staining, ×20; A2. Hematoxylin and eosin staining, ×40; B1. Periodic acid–Schiff staining, ×10; B2. Periodic acid–Schiff staining, ×40; C. Methenamine silver staining, ×40; D. MUC5B staining, ×40).