Follicular bronchiolitis: A rare cause of cystic lung disease.
Hanlon K, Stone C, and Morris Z. Follicular bronchiolitis: A rare cause of cystic lung disease. Chest 2017; 152(4):A437.
Follicular bronchiolitis is an uncommon lymphoproliferative lung disease characterized by lymphoid hyperplasia isolated to the airways. It has been described as occurring in collagen vascular diseases, especially rheumatoid arthritis and Sjögren's syndrome. Computed tomography (CT) characteristics are typically centrilobular/peribronchial nodules and ground glass opacities (GGOs).1 It has only rarely been reported as a cause of cystic lung disease.2 We report a case of follicular bronchiolitis in a patient with Sjögren's and MALT lymphoma presenting as progressive cystic lung disease with interstitial lung disease (ILD). CASE PRESENTATION: A 66-year-old male nonsmoker with a history of Sjögren's and MALT lymphoma was referred to the pulmonary clinic ten years prior for several 1-2 cm GGOs on CT. Also noted in each lobe were a few 1-2 cm cystic-like areas described as emphysematous. Over the last few years on periodic CT scans, obtained predominantly for lymphoma surveillance, there was a marked increase in the number and size of the cysts with associated interstitial and fibrotic changes, especially at the bases. He also began having intermittent cough and dyspnea with progressive decline in diffusing capacity from 93% to 59% of predicted. Suspecting lymphocytic interstitial pneumonitis (LIP), VATS was performed. Histopathologic findings revealed follicular bronchiolitis with fibrosis. He was treated with low dose corticosteroids for six months with resolution of his symptoms and partial radiographic improvement of the ILD. DISCUSSION: This patient appeared to have classic LIP, with progressive cystic lung disease and ILD associated with Sjögren's and MALT lymphoma. Only on lung biopsy, with extensive pathological examination and special staining, was this excluded. The sole remaining finding was progressive follicular bronchiolitis, with fibrosis, and cystic lung disease. CONCLUSIONS: Follicular bronchiolitis secondary to Sjögren's, though uncommon, is described in the literature. Follicular bronchiolitis causing cystic lung disease is exceedingly rare with only five prior cases reported.