[Two cases of pulmonary Mycobacterium xenopi infection]

We report on two patients diagnosed as having Mycobacterium xenopi infections. Case 1 occurred in a 40-year-old man. His chest radiograph revealed a cavitary lesion with a granular shadow in the right upper lung field. His sputum and bronchial lavage were negative for acid-fast bacilli and malignant cells. For a definitive diagnosis, lung resection was performed by video-assisted thoracoscopy. Case 2 was in a 45-year-old man. His chest radiograph showed a cavitary lesion with infiltration in the right upper lung field. Acid-fast bacilli were seen in his sputum specimens and M. xenopi was identified by culture. Despite medication with isoniazide, rifampicin and ethambutol, the infiltrative shadow in his radiograph increased in size. In this case, right upper lobectomy was performed. In recent years, 8 cases of pulmonary Mycobacterium xenopi infection have been reported in Japan. In the future, the number of such case reports may increase as a result of diagnosis by molecular biological methods. It is necessary to consider carefully whether surgical resection is required when chemotherapy is refused by the patient or is likely to be unsuccessful.