Uncommon mycosis in a patient with diabetes

Exploring a Rare Pulmonary Coinfection: Cryptococcal Pneumonia and Exophiala dermatitidis in an Immunocompetent Host

Pulmonary cryptococcosis is becoming increasingly common in immunocompetent hosts, manifesting with variable clinical presentations ranging from asymptomatic colonization to severe pneumonia. Radiological findings are non-specific, such as nodular infiltrates, mass-like lesions, and mediastinal lymphadenopathy. We present a case of a 61-year-old woman with Cryptococcus neoformans pneumonia coinfected with Exophiala dermatitidis, an unusual occurrence in an immunocompetent host and the first of its kind. This coinfection posed significant diagnostic challenges due to the rare occurrence of each individual organism in immunocompetent patients as well as the difficulty of their laboratory diagnosis. Treatment regimens, particularly in coinfections, warrant careful consideration to mitigate mortality risk. This case underscores the importance of comprehensive diagnostic strategies and optimized treatment regimens for rare fungal coinfections in immunocompetent hosts.

Cryptococcus: History, Epidemiology and Immune Evasion

Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.

A unique case report of endobronchial cryptococcosis and review of the literature

Cryptococcosis is an infection caused by the yeast-like fungus Cryptococcus neoformans. Pulmonary cryptococcosis is typically identified as a single mass or as multiple nodules, while endobronchial lesions are quite rare. Here we report an uncommon case of pulmonary cryptococcosis presenting as endobronchial lesion in an immunocompetent patient. A 49-year-old male patient complained of intermittent cough with hemoptysis for two years. Computerized tomography of the chest showed a filling defect in the basal segment of the right lower lobe bronchus. A flexible bronchoscopic examination revealed a white smooth-surfaced polypoid lesion completely occluding the medial basal segment of the right lower lobe bronchus. The diagnosis was confirmed by bronchial biopsy under bronchoscopy, and the histopathologic findings showed the organisms were Cryptococcal neoformans. The patient was treated with fluconazole at a dose of 400 mg daily. The endobronchial lesion was found rapidly diminished after 18 days of therapy, and disappeared after 6.5 months of therapy by repeated fiberoptic bronchoscopy. Then the patient continued fluconazole for another 2.5 months. During the total 16 months' follow-up visits, the patient repeated CT scanning for five times, the results of which were all normal. The patient's symptoms disappeared as well, and now he is still under follow-up. This case highlights the fact that pulmonary cryptococcosis can present as endobronchial lesions even in immunocompetent subjects, mimicking lung tumor. Pathological confirmation is important to establish the definite diagnosis.