Oral Cryptococcosis due to <i>Naganishia diffluens</i> in a Patient With Thalassemia: A Case Report and a Literature Review

BACKGROUND: Naganishia diffluens (formerly Cryptococcus diffluens) is a non-neoformans cryptococcal species rarely isolated as a human pathogen. We reported a case of oral cryptococcosis caused by N. diffluens for the first time and reviewed relevant literature. METHODS: Herein, we present the case of a 31-year-old Iranian male with a history of major β-thalassemia, who presented with non-hemorrhagic white spots on the buccal mucosa, the mouth, lips, and the tongue's surface. Abdominal ultrasound results of the pelvis and abdomen showed that the patient has significant splenomegaly. Two consecutive samples were collected from the white spots on the patient's tongue to confirm the infection, which was confirmed via PCR Sequencing analysis. RESULTS: In both sampling occasions, Naganishia diffluens was isolated as the causative organism. According to a review conducted in PubMed, Web of Science, and Scopus for data analysis of oral cryptococcosis, just 27 reports were described in the literature. Naganishia diffluens can be the causative agent of some infections. CONCLUSION: This is the first report of oral cryptococcosis due to N. diffluens successfully detected by DNA sequencing. However, to understand the precise prevalence of this emerging pathogen, epidemiological surveillance studies are highly recommended.