Pulmonary Cryptococcosis in a Diabetic Patient Without Severe Immunosuppression: Case Report and 25-Year Literature Review

Abstract

Pulmonary cryptococcosis is an invasive fungal infection usually linked to severe immunosuppression, particularly HIV/AIDS, but is increasingly reported in immunocompetent hosts, including those with uncontrolled diabetes mellitus (DM). We describe a 51-year-old woman with poorly controlled type 2 DM and no other immunosuppressive conditions who developed pulmonary cryptococcosis. Diagnosis was made by microscopy, India ink, cryptococcal antigen lateral flow assay (CrAg LFA), and ITS sequencing; culture was negative. Despite treatment with deoxycholate amphotericin B and fluconazole, the patient died 36 days after admission. A systematic literature review (2000–2025) identified 40 cases of pulmonary cryptococcosis, with 17.5% occurring in patients whose only comorbidity was DM. Cryptococcus neoformans was the most frequent species. Non-culture-based methods, especially CrAg detection, were widely used, underscoring their value for rapid and sensitive diagnosis. Pulmonary cryptococcosis should be considered in diabetic patients even without classical immunosuppression. Broader use of non-culture-based diagnostic tools may enable earlier intervention, which is particularly relevant in resource-limited settings such as Honduras.