Misdiagnosis of invasive pulmonary fungal disease caused by drug-resistant Candida tropicalis as airway neoplasm: case report and literature review

Invasive pulmonary fungal disease (IPFD) is often missed or misdiagnosed. Here we report a rare case of IPFD caused by multidrug-resistant Candida tropicalis , which was initially misdiagnosed at another hospital as recurrent pulmonary lymphoma because the patient had a history of lymphoma. Histopathology, sputum culture, and next-generation sequencing of bronchoalveolar lavage fluid at our hospital indicated that IPFD was caused by C. tropicalis . The patient did not respond to fluconazole but showed substantial improvement with caspofungin. We discovered a cutaneous malignancy, which we determined to be the most likely cause of the immunosuppression that facilitated invasive C. tropicalis infection. Our case highlights that IPFD caused by C. tropicalis can show unusual manifestations, which can lead to misdiagnosis as malignancy; that response to antifungals should be monitored carefully because of the risk of resistance in circulating C. tropicalis strains; and that underlying causes of the immunosuppression that led to C. tropicalis infection should be explored, which may uncover deeper problems.