Microsporidium detected in clinical specimens from a stem cell transplant patient who had undergone substantial immunosuppression. A) Calcofluor white–stained ascitic fluid (original magnification ×500). B) Hematoxylin and eosin–stained skin biopsy sample (original magnification ×400). The arrow indicates clusters of spores. C) Warthin-Starry–stained skin biopsy sample (original magnification ×400). The arrows indicate clusters of spores. D) Modified trichrome–stained material from bronchoalveol