Leprosy is a chronic granulomatous infection caused by Mycobacterium leprae and the respiratory tract, the entry point of leprosy. A 29-year-old man was diagnosed with a sinonasal tumor based on a history of chronic rhinosinusitis symptoms and planned to undergo surgery. Before surgery, the patient was referred to a dermatologist for complaints of generalized erythematous nodules with pain and was diagnosed with leprosy based on histopathologic examination. After three weeks of treatment, the patient's condition improved significantly in both skin lesions and sinonasal tumors.