Which fungus is a major cause of invasive pulmonary disease in immunocompromised hosts?

Which fungus is a major cause of invasive pulmonary disease in immunocompromised hosts?

• A. Histoplasma capsulatum
• B. Cryptococcus neoformans
• C. Coccidioides immitis
• D. Aspergillus fumigatus

Answer: (D)

Invasive pulmonary disease in immunocompromised patients is most often driven by angioinvasive molds. Aspergillus fumigatus fits this scenario best because, in neutropenic or severely immunosuppressed individuals, inhaled spores germinate and the hyphae invade blood vessels in the lung. This vascular invasion leads to tissue necrosis and hemorrhagic infarcts, producing rapidly progressive pulmonary disease and distinctive imaging findings. Pathology shows septate hyphae with acute-angle branching, consistent with Aspergillus. The other fungi listed are associated with different patterns: Histoplasma capsulatum tends toward granulomatous or disseminated disease in varied hosts; Cryptococcus neoformans often causes meningitis in immunocompromised patients; Coccidioides immitis can cause pneumonia and disseminate but is not the quintessential cause of invasive pulmonary disease in the neutropenic setting.

Invasive pulmonary disease in immunocompromised patients is most often driven by angioinvasive molds. Aspergillus fumigatus fits this scenario best because, in neutropenic or severely immunosuppressed individuals, inhaled spores germinate and the hyphae invade blood vessels in the lung. This vascular invasion leads to tissue necrosis and hemorrhagic infarcts, producing rapidly progressive pulmonary disease and distinctive imaging findings. Pathology shows septate hyphae with acute-angle branching, consistent with Aspergillus. The other fungi listed are associated with different patterns: Histoplasma capsulatum tends toward granulomatous or disseminated disease in varied hosts; Cryptococcus neoformans often causes meningitis in immunocompromised patients; Coccidioides immitis can cause pneumonia and disseminate but is not the quintessential cause of invasive pulmonary disease in the neutropenic setting.