Follicular bronchiolitis is an uncommon bronchiolar disorder that is characterized by the presence of hyperplastic lymphoid follicles with reactive germinal centers. The condition is associated with connective tissue diseases such as rheumatoid arthritis, Sjögren's syndrome, and immunodeficiency disorders. A 56-year-old man with rheumatoid arthritis was admitted to hospital with a progressively enlarging pulmonary nodule in the left upper lobe. A follow-up contrast tomography scan showed that the nodule had increased in size from 4.2 mm to 6.3 mm over a 3 month period. An open lung biopsy was performed to establish a definite pathologic diagnosis of the pulmonary nodule, which was suspected to be a lung malignancy. The nodule was diagnosed as follicular bronchiolitis based on the histopathology findings. We describe a patient with follicular bronchiolitis that was confirmed by an open lung biopsy, and is believed to have had rheumatoid involvement.