The following describes the case of a healthy 29-year-old man whose chest radiography at the time of medical examination revealed a solitary pulmonary nodule without a tree-in-bud pattern and a cavity in the upper right lung. Histopathological findings of samples obtained by bronchoscopic biopsy showed nonspecific inflammation, and bronchial lavage was negative for acid-fast bacilli and bacterial culture. Because the nodule had a high FDG uptake on PET/CT imaging, it was suspected to be lung cancer. For a definitive diagnosis, partial resection of the right upper lobe was performed by video-assisted thoracoscopy. Histopathological examination of tissue samples obtained from the right upper lung revealed epithelioid granuloma, and culture from the samples grew Mycobacterium xenopi. We then performed DNA sequence analysis to distinguish between M. xenopi and Mycobacterium heckeshornense. The analysis demonstrated that the acid-fast bacilli cultured from the samples were M. xenopi. A lung infection by M. xenopi was diagnosed in this patient. Although the patient received no chemotherapy for M. xenopi infection after surgery, no recurrence has been observed.