[A case of nontuberculous mycobacterial disease and malignant lymphoma in an elderly patient].

An 88-year-old woman was referred to our hospital due to body weight loss (9 kg) over one year. Bronchoscopy revealed Mycobacterium avium, and antimicrobial treatment was initiated. Three months later, a chest CT scan revealed a mass shadow in the left lingular segment. After a second bronchoscopic examination, a pathological diagnosis of diffuse large B-cell lymphoma was made. After one course of chemotherapy, the mass in the left middle lobar significantly decreased in size. We report a case of malignant lymphoma with NTM in an elderly patient. Impaired immunity may have played a role in the development of both diseases. In an aging society, complications associated with both diseases may increase. Careful and detailed examination is essential.