Figure. Histopathologic characteristics of rhinosporidiosis, Eastern Province, Rwanda, 2014–2016. A) At scanning magnification, multiple cystic structures (sporangia) of variable sizes are embedded in respiratory mucosa in a background of mononuclear inflammation (hematoxylin and eosin [H&E] stain; original magnification ×40). B) R. seeberi early juvenile sporangium, with a well-delimited cell wall, granular cytoplasm, and reddish nucleus with prominent nucleolus, characteristic of this stage (H&E stain; original magnification ×400). C) R. seeberi mature sporangium. Maturation of the endoconidia occurs from the periphery to the center of the cyst (H&E stain; original magnification ×600). Inset shows the spherules of coccidioides are smaller (up to 80 μm) and contain endospores of similar size, which appear as clear vacuoles (arrow) on stained sections (H&E stain; original magnification ×600). D) Both the cyst wall and endospores stain with the methenamine silver reaction, with discontinuity of the cyst wall at the upper pole, corresponding to the cyst pore zone (Grocott methenamine silver; original magnification ×400).