Home   Chapter Home   Jobs   Conferences   Fellowships   Books




Cryptococcus neoformans

Reviewer: Elliot Weisenberg, M.D. (see Reviewers page)
Revised: 27 March 2014, last major update September 2011
Copyright: (c) 2003-2011, PathologyOutlines.com, Inc.

Clinical features

● Yeast, mostly encapsulated, found in pigeon droppings, that may cause mild infection after inhalation; usually confluent bronchopneumonia with “yeast lakes” of microorganisms and possibly coin lesions, but no evident host response (eMedicine)
● May also cause meningitis
● Latent infections can reactivate in immunosuppressed
● CNS disease is a major concern in immunocompromised
● Most commonly an opportunistic infection, but disease may occur in immunocompetent patients
● Major virulence factor is capsular polysaccharide glucuronoxylomannin, which hinders phagocytosis by alveolar histiocytes and inflammatory cell recruitment and migration
● Other virulence factors include melanin production (Fontana-Masson stain may be positive; melanin may have anti-oxidant properties) and enzymes that increase invasiveness

Case reports

● 65 year old woman with arthritis and lung mass (Case of the Week #298)

Micro description

● Somewhat pleomorphic, round/oval yeast, 4-10 microns
● Thick, mucinous capsule stains bright red with mucicarmine; some are unencapsulated
● Narrow necked budding takes place
● Smaller, unencapsulated forms resemble Histoplasma capsulatum

Micro images

Various images

Case of the Week #298:
Frozen section

Oil Immersion images


PAS stain

End of Lung-nontumor > Infections > Cryptococcus neoformans

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at [email protected] with any questions (click here for other contact information).