First human pleural infection caused by Naganishia globosa (formerly Cryptococcus saitoi).

Naganishia globosa (formerly Cryptococcus saitoi) is an environmental basidiomycetous yeast rarely associated with human disease. We report the first case worldwide of N. globosa isolated from pleural fluid in a patient with T-cell acute lymphoblastic leukemia (T-ALL), an immunocompromised host, hospitalized in Türkiye. The isolate was identified by MALDI-TOF MS and confirmed by molecular sequencing. The patient received antifungal therapy following diagnosis. Liposomal amphotericin B, isavuconazole, fluconazole, and voriconazole were used in the patient's treatment and were modified according to drug tolerance and clinical condition. The absence of yeast growth in follow-up pleural cultures and the patient's survival 1.5 months after discharge indicate a favorable response to therapy. This case highlights the clinical relevance of this uncommon yeast in immunocompromised individuals and underscores the importance of advanced diagnostic tools for accurate identification and increased awareness of rare fungal pathogens.