Opportunistic infections | Figure 4.33
A: Cryptococcus neoformans
(Courtesy of Doctor Fungus,
www.doctorfungus.org)
B: Mucormycosis
(Courtesy of Dr. Paul Getz)
C: Mucor spp.*
D: Rhizopus spp .*
*Courtesy of Sandra Arduin,
Michigan Department of
Community Health |
(Figure 4.33A) - Cryptococcus neoformans, dimorphic fungus with characteristic polysaccharide capsule, found in pigeon droppings, soil, and dust
- Transmission via inhalation
- Presentation:
- Primary pulmonary infection: asymptomatic or mild infection in an immunocompetent person, but immunocompromised person may have disseminated disease (can spread to CNS, bone, skin); secondary skin lesions are polymorphous (molluscum-like umbilicated papules, acneiform pustules, papules, nodules, abscesses, etc.)
- Primary cutaneous infection (inoculation): extremely rare
- Histology: encapsulated yeast (2–12 µm), ± single or budding, mucoid capsule stains well with mucicarmine, PAS, Alcian blue; India ink stains yeast (capsule appears as clear halo)
- Gelatinous pattern: numerous budding yeast, capsule does not stain which gives dermis vacuolated gelatinous appearance, minimal inflammation
- Granulomatous pattern: pseudoepitheliomatous hyperplasia, granulomatous infiltrate with fewer yeast
- Treatment: amphotericin B ± flucytosine
|
