Clinicopathologic and ultrastructural study of non-HIV-related primary pulmonary cryptococcosis in China: report of 43 cases

Comparison of the clinical manifestations and chest CT findings of pulmonary cryptococcosis in immunocompetent and immunocompromised patients: a systematic review and meta-analysis

Objective

The purpose of our study was to perform a meta-analysis and systematic review to compare differences in clinical manifestations and chest computed tomography (CT) findings between immunocompetent and immunocompromised pulmonary cryptococcosis (PC) patients.

Methods

An extensive search for relevant studies was performed using the PubMed, EMBASE, Cochrane Library, and Web of Sciences databases from inception to September 30, 2021. We included studies that compared the clinical manifestations and chest CT findings between immunocompetent and immunocompromised PC patients. Study bias and quality assessment were performed using the Newcastle–Ottawa Scale (NOS).

Results

Nine studies involving 248 immunocompromised and 276 immunocompetent PC patients were included in our analysis. The NOS score of each eligible study was above 5, indicating moderate bias. The proportion of elderly patients (> = 60 years old) in the immunosuppressed group was significantly higher than that in the immunocompetent group (OR = 2.90, 95% CI (1.31–6.43), Z = 2.63, p = 0.01). Fever (OR = 7.10, 95% CI (3.84–13.12), Z = 6.25, p < 0.000) and headache (OR = 6.92, 95% CI (2.95–16.26), Z = 4.44, p < 0.000) were more common in immunosuppressed patients. According to thin-section CT findings, lesions were more frequently distributed in the upper lobe (OR = 1.90, 95% CI (1.07–3.37), Z = 2.2, p = 0.028) in immunocompromised individuals. The proportions of patients with cavity sign (OR = 5.11, 95% CI (2.96–8.83), Z = 5.86, p = 0.00), ground-glass attenuation (OR = 5.27, 95% CI (1.60–17.35), Z = 2.73, p = 0.01), and mediastinal lymph node enlargement (OR = 2.41, 95% CI (1.12–5.20), Z = 2.24, p = 0.03) were significantly higher in immunocompromised patients.

Conclusion

No significant differences in nonspecific respiratory symptoms were found between immunocompromised and immunocompetent PC patients. Nevertheless, fever and headache were more common in immunocompromised patients. Among the CT findings, cavity, ground-glass attenuation, and mediastinal lymph node enlargement were more common in immunocompromised individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02175-9.

Cryptococcal antigen testing of lung tissue homogenate improves pulmonary cryptococcosis diagnosis: Two case reports

BACKGROUND

Pulmonary cryptococcosis (PC) is an opportunistic infectious disease of the respiratory system. Lung tissue biopsies, culture of respiratory samples (e.g., sputum, lung tissue, pleural fluid, and bronchoalveolar lavage fluid), and cryptococcal antigen (CrAg) testing are helpful for a definitive diagnosis. However, these tests are sometimes falsely negative. PC is often misdiagnosed or underdiagnosed owing to the absence of obvert symptoms, poor imaging specificity, and false-negative laboratory tests.

CASE SUMMARY

We report two female patients who underwent computed tomography-guided percutaneous needle pulmonary biopsy of a lung nodule for a confirmed diagnosis. In both patients, the CrAg test on the lung biopsy tissue homogenate was positive, while the serum CrAg test was negative. Combined with the lung tissue pathology, we made the diagnosis of PC. Antifungal therapy was effective in both patients.

CONCLUSION

Given the findings of our cases and the literature review, lung tissue homogenate CrAg testing can be helpful in improving the diagnosis of PC.

Cryptococcus infection with asymptomatic diffuse pulmonary disease in an immunocompetent patient: A case report

BACKGROUND

Cryptococcus presenting as an opportunistic pathogen mainly affects immunocompromised patients, but the disseminated form of infection is rare among immunocompetent populations. The partial radiographic characteristics of pulmonary cryptococcosis mimic lung carcinoma, leading to unnecessary open chest exploratory surgery, and the lack of a gold-standard noninvasive diagnostic increases the risk of misdiagnosis. Positron emission tomography/computed tomography (PET/CT), a sensitive method for distinguishing malignant tumors, coupled with cryptococcal latex agglutination test showing a high positive rate may overcome these issues.

CASE

A 36-year-old man presented for general examination, without health complaints. Routine CT showed multiple pulmonary nodules and a mass with high maximum standardized uptake value. Initially, we suspected primary malignancy with hematogenous metastasis. Although his routine fungal analysis had been negative, subsequent CT-guided percutaneous core needle biopsy and histopathology examination indicated a diagnosis of pulmonary cryptococcosis. Fluconazole (200 mg/d) antifungal drug treatment was initiated, and 1 mo later the pulmonary mass had reduced in size markedly (on chest CT scan) without any complications.

CONCLUSION

Serologic and PET/CT examinations may not rule out cryptococcosis, and percutaneous lung puncture is critical under all circumstances.

Dormancy in Cryptococcus neoformans: 60 years of accumulating evidence

Cryptococcus neoformans is an opportunistic yeast that is present worldwide and interacts with various organisms. In humans, it is responsible for cryptococcosis, a deadly invasive fungal infection that represents around 220,000 cases per year worldwide. Starting from the natural history of the disease in humans, there is accumulating evidence on the capacity of this organism to enter dormancy. In response to the harsh host environment, the yeast is able to adapt dramatically and escape the vigilance of the host's immune cells to survive. Indeed, the yeast exposed to the host takes on pleiotropic phenotypes, enabling the generation of populations in heterogeneous states, including dormancy, to eventually survive at low metabolic cost and revive in favorable conditions. The concept of dormancy has been validated in C. neoformans from both epidemiological and genotyping data, and more recently from the biological point of view with the characterization of dormancy through the description of viable but nonculturable cells.

Animal Models of Cryptococcus neoformans in Identifying Immune Parameters Associated With Primary Infection and Reactivation of Latent Infection

Cryptococcus species are environmental fungal pathogens and the causative agents of cryptococcosis. Infection occurs upon inhalation of infectious particles, which proliferate in the lung causing a primary infection. From this primary lung infection, fungal cells can eventually disseminate to other organs, particularly the brain, causing lethal meningoencephalitis. However, in most cases, the primary infection resolves with the formation of a lung granuloma. Upon severe immunodeficiency, dormant cryptococcal cells will start proliferating in the lung granuloma and eventually will disseminate to the brain. Many investigators have sought to study the protective host immune response to this pathogen in search of host parameters that keep the proliferation of cryptococcal cells under control. The majority of the work assimilates research carried out using the primary infection animal model, mainly because a reactivation model has been available only very recently. This review will focus on anti-cryptococcal immunity in both the primary and reactivation models. An understanding of the differences in host immunity between the primary and reactivation models will help to define the key host parameters that control the infections and are important for the research and development of new therapeutic and vaccine strategies against cryptococcosis.

A case of pulmonary cryptococcosis with large pericardial effusion diagnosed using cervical lymph node biopsy

Pulmonary cryptococcosis (PC) is a relatively rare infectious disease. It mainly involves the lungs; however, in some patients, the infection could spread to other parts of the body. PC mostly occurs in patients with immune deficiencies. However, PC infections have been reported in non-immunocompromised patients. The diagnosis of PC is challenging in patients without immune deficiencies. Here, the case of a 27-year-old immunocompetent woman who was diagnosed with PC was report. She had unexplained fever and a history of close contact with poultry feathers. Lesions were observed in the lungs, pleural cavity, pericardium, and cervical lymph nodes. Biopsy of the cervical lymph nodes helped in the pathological diagnosis of PC. She was treated with fluconazole, and the lesions disappeared. They present this case to encourage detailed inquiry of medical history in such patients, improve the diagnostic awareness of clinicians, and help reduce the likelihood of misdiagnosis.