Fig. 4.

Acute invasive fungal rhinosinusitis a low power view of infarcted sinonasal without significant inflammatory reaction in immunosuppressed patient with acute leukemia with acute invasive fungal rhinosinusitis Culture grew Rhizopus sp. (Hematoxylin and eosin; original magnification ×12.5). b Acute invasive FRS showing fungal organisms invading blood vessels and soft tissue. Cultures grew Aspergillus fumigatus (Hematoxylin and eosin; original magnification ×100). c Silver staining highlighting fungal hyphae in soft tissue in acute invasive FRS. Cultures grew A. fumigatus (Hematoxylin and eosin; original magnification ×100). d In situ hybridization (ISH) for Aspergillus ribosomal RNA. Note the extensive necrosis and only rare positive organisms. rRNA ISH is not always reliable on necrotic tissues (Fast red tetrazolium violet; original magnification ×100)