Abstract
Antitumor necrosis factor-associated nontuberculous mycobacteria-immune reconstitution inflammatory syndrome (IRIS) has rarely been reported. An 84-year-old woman with a history of rheumatoid arthritis treated with etanercept was diagnosed with Mycobacterium avium complex (MAC) pulmonary disease six years before admission. Etanercept was discontinued two years ago because of MAC pulmonary disease progression and restarted nine months before admission because of worsening arthritis, again resulting in MAC pulmonary disease progression. Etanercept was discontinued again; however, the pulmonary disease progressed more rapidly. The condition was considered paradoxical worsening caused by IRIS due to etanercept discontinuation. The disease resolved quickly with chemotherapy for MAC.