Comparison of laboratory diagnosis, clinical manifestation, and management of pulmonary cryptococcosis: Report of the clinical scenario and literature review

Clin Chim Acta. 2022 Jan 1;524:78-83. doi: 10.1016/j.cca.2021.11.017. Epub 2021 Nov 27.


Background: Pulmonary cryptococcosis is an opportunistic aggressive mycosis in immunocompromised patients, but it can be increasingly seen in immunocompetent patients. It is still challenging to make a rapid and accurate diagnosis due to the various clinical manifestations and limitations in the diagnostic tools.

Method: A 54-year-old man presented with intermittent productive cough and fever for 1 week. A chest X-ray demonstrated multiple consolidations in both lungs. Blood biochemistry indicated elevated immunoglobulin G levels. Including sputum cultures, polymerase chain reaction (PCR) tests for severe acute respiratory syndrome coronavirus 2, influenza A and B virus were all negative. Computed tomography of the chest showed ground-glass opacities with a nodular pattern. The serum cryptococcal antigen test was positive; however, the cerebral spinal fluid was negative. The diagnosis of pulmonary cryptococcal infection was made. An initial bronchoscopy was performed unsuccessfully and the patient received intravenous fluconazole therapy for 2 weeks. Due to poor improvement of clinical condition, he then underwent a surgical lung biopsy. The pathology revealed several encapsulated yeast cells, diffuse pulmonary interstitial fibrosis, noncaseating granulomas surrounded by T lymphocytes and multinucleated giant cells with intracellular inclusions, confirming pulmonary yeast infection associated with hypersensitivity pneumonitis. Ultimately, fungal cultures of the pathology samples revealed Cryptococcus neoformans. Subsequently antifungal therapy combined with oral steroid treatment, his general condition improved. After a total of 6 months of antifungal therapy, the patient recovered completely.

Conclusions: Applicable laboratory diagnosis can help facilitate the accurate and rapid diagnosis of pulmonary cryptococcosis. This report elected to provide an update on the topic of laboratory diagnosis, clinical manifestation, and management of pulmonary cryptococcosis.

Keywords: Cryptococcal antigen; Cryptococcal infection; Cryptococcus neoformans; Hypersensitivity pneumonitis; Immunoglobulin G; Pulmonary cryptococcosis.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Biopsy
  • COVID-19*
  • Cryptococcosis* / diagnosis
  • Cryptococcosis* / drug therapy
  • Humans
  • Male
  • Middle Aged
  • Pulmonary Fibrosis*
  • SARS-CoV-2