Figure 2. A) Cysts in a vessel wall (arrows) of the patient (hematoxylin and eosin stain, magnification ×250). Inset shows a cyst at higher magnification (hematoxylin and eosin stain, magnification ×800). B) Immunohistochemical staining with antibody to Acanthamoeba cysts within vessel walls (magnification ×250). C) Polyacrylamide gel electrophoresis of PCR products for Acanthamoeba spp., Naegleria spp., and Balamuthia mandrillaris using JDP primers for a diagnostic small subunit rDNA fragment. M, molecular mass marker; Pat, patient; Neg, negative control; Pos, positive control.