Pulmonary sarcoidosis with a cavitary lesion in the lung caused by a TNF‐α inhibitor: A case report

A 28‐year‐old man with ankylosing spondylitis (AS) who was treated with a tumour necrosis factor‐alpha (TNF‐α) inhibitor, adalimumab, presented with newly detected multiple bilateral pulmonary nodules on chest computed tomography (CT). We suspected bacterial infection, including those caused by acid‐fast bacilli, or adalimumab‐related condition, such as sarcoidosis. After adalimumab cessation, no resolution of the pulmonary shadows was observed. Moreover, pulmonary cavitation appeared on chest CT at 7 weeks, prompting surgical lung biopsy. Acid‐fast bacteria culture of the lung tissue showed negative results. Pathological examination suggested that confluent granulomas associated with sarcoidosis might have obstructed the blood vessels, causing necrosis and lung cavitation. Consequently, prednisolone was initiated, and these shadows were reduced. After administering anti‐interleukin (IL)‐17A antibody for treatment of AS and prednisolone withdrawal, these shadows were not exacerbated. TNF‐α inhibitor‐induced sarcoidosis could cause cavitary lesions due to vascular invasion of granulomas.