Lung

Infectious

Fungal

Other fungi



Topic Completed: 1 September 2011

Minor changes: 26 March 2021

Copyright: 2003-2021, PathologyOutlines.com, Inc.

PubMed search: blastomyces [title] lungs, candida [title] lungs, cryptococcus neoformans [title] pulmonary, mucor [title] pulmonary

Elliot Weisenberg, M.D.
Page views in 2021 to date: 1,685
Table of Contents
Blastomyces | Candida | Cryptococcus | Mucor
Cite this page: Weisenberg E. Other fungi. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungnontumorotherfungi.html. Accessed October 25th, 2021.
Blastomyces

Clinical features
  • See also Skin - nontumor chapter
  • Dimorphic fungus found in soil in Central and Southeastern United States and Canada (bordering Great Lakes, St. Lawrence River, Mississippi River and Ohio River basins), Mexico, Africa, India, Middle East
  • More common in males
  • Due to inhalation of soil containing microfoci of mycelia (Clin Microbiol Rev 2010;23:367)
  • Difficult to isolate in clinical microbiology laboratory
  • May present as consolidative pneumonia, ARDS or nodules resembling carcinoma; prefers upper lobes
  • May also infect skin and bone
  • Grossly often resembles tuberculosis

Microscopic (histologic) description
  • Mixed acute and granulomatous inflammation caused by large budding yeasts (15 - 10 μm) with broad based buds and refractile walls
  • Easily seen with H&E

Microscopic (histologic) images

Images hosted on other servers:
Various images (skin or sputum)

Typical appearance of B. dermatitidis

Various images (skin or sputum)

Microabscess with a nonbudding yeast cell

Various images (skin or sputum) Various images (skin or sputum)

Budding yeast of B. dermatitidis

Candida

Definition / general
  • See also Skin - nontumor chapter
  • Normal flora of mouth, GI tract, vagina
  • May be commensal or pathogen
  • Commonly present in upper airways
  • Often present in aspiration pneumonia or pulmonary abscess due to colonization but invasive disease due to candida is rare in lung except in setting of candidal sepsis
  • Candida pneumonia associated with malignancy or immunosuppression (West J Med 1979;131:196)

Microscopic (histologic) description
  • Pseudohyphae, occasionally true hyphae and budding yeasts
  • In some cases, only yeast may be present

Microscopic (histologic) images

Contributed by Yale Rosen, M.D.
Lung: GMS staining Lung: GMS staining

Lung: GMS staining



Images hosted on other servers:
Candida

Candida



Positive stains
Cryptococcus

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: Cryptococcosis [Accessed 22 March 2021])
  • 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 antioxidant properties) and enzymes that increase invasiveness

Case reports

Microscopic (histologic) 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

Microscopic (histologic) images

Case #298
Frozen section Frozen section Frozen section Frozen section

Frozen section

Oil immersion images Oil immersion images

Oil immersion images


Oil immersion images Oil immersion images

Oil immersion images

H&E H&E H&E H&E

H&E


PAS stain

PAS stain



Images hosted on other servers:
Various images

Large mucoid capsule

Various images

Cryptococcosis in patient with AIDS

Mucor

Definition / general
  • Also known as zygomycosis or mucormycosis
  • Ubiquitous fungi of class Zygomycetes, includes Mucor, Rhizopus, Absidia and Cunninghamella
  • Opportunistic infection especially associated with diabetes; other predisposing factors are neutropenia, corticosteroid therapy, iron overload and mucocutaneous trauma
  • Pulmonary and sinusoidal infection caused by inhaled spores or secondary to rhinocerebral mucormycosis

Case reports

Microscopic (histologic) description
  • Large, nonsepta hyphae with 90 degree angle branching and nonparallel walls, angioinvasive causing tissue necrosis and hemorrhage

Microscopic (histologic) images

Images hosted on other servers:
Culture shows young sporangia of Mucor species

Culture shows young sporangia of Mucor species

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