LAUSR

BACKGROUND Cladosporium and Corynespora cassiicola (C. cassiicola) infections rarely occur in humans. Mutations in human caspase recruitment domain protein 9 (CARD9) are reported to be associated with fungal diseases. Pulmonary Cladosporium infection coexisting with subcutaneous C. cassiicola infection in a patient with a CARD9 mutation has not been reported in the literature. CASE SUMMARY A 68-year-old male patient was hospitalized for hypertrophic erythema and deep ulcers on the left upper extremity. He was diagnosed with pneumonia caused by Cladosporium, as identified through bronchoalveolar lavage fluid analysis, and deep dermatophytosis caused by C. cassiicola, as identified through morphological characteristics of the wound secretion culture. He underwent antifungal therapy (voriconazole) and recovered successfully. He carried two mutations in CARD9 (chr9:139266425 and chr9:139262240) and was therefore susceptible to fungal infections. CONCLUSION This case study is the first to report the coexistence of pulmonary Cladosporium infection and subcutaneous C. cassiicola infection in a patient with CARD9 mutation. Our findings will be helpful in enriching the phenotypic spectrum of fungal infections underlying CARD9 deficiency.