Palatal perforation caused by Alternaria alternata infection in an immunocompetent adolescent

Opportunistic oral mucosal fungal infection caused by Alternaria alternata is extremely rare. Herein, we present a rare palatal perforation as a result of oral infection caused by A. alternata in an immunocompetent adolescent. An 18-year-old boy, who had previously been healthy, was admitted to our institution with persistent pain in the palate for the past 12 months. Upon impression of palatal bone resorption based on computed tomography imaging and chronic granulomatous inflammation based on biopsy (hematoxylin-eosin staining), the patient was examined for commonly relevant causes such as potential tumor and Mycobacterium tuberculosis infection. All test results were inconclusive. After a thorough diagnostic investigation, an unusual fungal infection, A. alternata infection, was confirmed by next-generation sequencing and biopsy (periodic acid-Schiff staining and immunofluorescence staining). The patient underwent surgical debridement and was subjected to voriconazole treatment postoperatively for over a period of 5 months. Thus, these findings highlight the importance of considering A. alternata as a potential pathogenic factor in an etiological palatal perforation.