Imaging findings of fibrosis in pulmonary sarcoidosis

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Michiru Sawahata
Tetsuo Yamaguchi


sarcoidosis, fibrosis, honeycombing, stage Ⅳ, non-caseating epithelioid granuloma, fibrosis, pleuroparenchymal fibroelastosis


Background: In pulmonary sarcoidosis, respiratory tract lesions almost always appear, and residual lung shadows require treatment in about 20% of cases. Pulmonary fibrosis is among the three leading causes of death. Treatment strategies are urgently needed to inhibit the progression of pulmonary fibrosis by combining antifibrotic drugs and immunosuppressive drugs such as corticosteroids. Establishing consensus on the process of pulmonary fibrosis progression is important for determining the most effective treatment.

Our review: Among more than 2500 cases of sarcoidosis treated at our hospital, cases that led to chronic respiratory failure were analyzed for CT findings of pulmonary fibrosis. Early in sarcoidosis, granulomatous lesions appeared along the bronchovascular bundle. As pulmonary fibrosis progressed, a central consolidation developed on the central side in the direction of lymph flow, a peripheral consolidation developed on the pleural side, and a central-peripheral band developed connecting the two. Infiltrative or wedge-shaped shadows sometimes formed in the immediate subpleural area, appearing as a pleuroparenchymal fibroelastosis-like lesion. Traction bronchiectasis may form cysts at the periphery or may congregate to form a honeycomb lung-like structure. Combination of these lesions led to shrinkage of the upper lobe. Patients with multiple peripheral cysts/bullae had a unique disease course characterized by wheezing and concomitant pulmonary hypertension and pulmonary aspergillosis.

Conclusion: Further understanding of the process of pulmonary fibrosis progression is needed. Summarizing imaging findings and understanding their contribution to respiratory impairment will contribute to comprehensively evaluating the stages of pulmonary fibrosis progression and establishing an optimal treatment strategy.


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1) Negi M, Takemura T, Guzman J, et al. Localization of Propionibacterium acnes in granulomas supports a possible etiologic link between sarcoidosis and the bacterium. Mod Pathol. 2012; 25: 1284-97.
2) Ishige I, Eishi Y, Takemura T, et al. Propionibacterium acnes is the most common bacterium commensal in peripheral lung tissue and mediastinal lymph nodes from subjects without sarcoidosis. Sarcoidosis Vasc Diffuse Lung Dis. 2005; 22: 33-42.
3) Sawahata M, Sugiyama Y. An epidemiological perspective on the pathology and etiology of sarcoidosis. Sarcoidosis Vasc Dis 2016; 33: 112-6.
4) Yamaguchi T, Eishi Y. [Sarcoidology Based on P. acnes Etiology.] JSSOG 2019; 39: 1-10.
5) Sawahata M, Sugiyama Y, Nakamura Y, et al. Age-related and historical changes in the clinical characteristics of sarcoidosis in Japan. Resp Med 2015; 109:272-8.
6) Sawahata M, Sugiyama Y, Nakamura Y, et al. Age-related differences in chest radiographic staging of sarcoidosis in Japan. Eur Respir J 2014; 43:1810-2.
7) Sawahata M, Shijubo N, Johkoh T, et al. Progression of central-peripheral band and traction bronchiectasis clusters leading to chronic respiratory failure in a patient with fibrotic pulmonary sarcoidosis. Intern Med 2021; 60: 111-6.
8) Sawahata M, Johkoh T, Kawanobe T, et al. Computed tomography images of fibrotic pulmonary sarcoidosis leading to chronic respiratory failure. J Clin Med 2020; 9 
9) Sawahata M, Johkoh T, Kawanobe T, et al T. Paradoxical Formation of a Pleuroparenchymal Fibroelastosis-like Lesion in the Chronic Course of Pulmonary Sarcoidosis. Intern Med. 2022; 61: 523-6.
10) Sawahata M, Shijubo N, Johkoh T, et al. Honeycomb lung-like structures resulting from clustering of traction bronchiectasis distally in sarcoidosis. Respirol Case Rep 2020; 8: e00539.
11) Sawahata M, Takemura T, Kawanobe T, et al. Honeycomb-like structures in sarcoidosis pathologically showing granulomas in walls of clustered bronchioles. Respirol Case Rep 2021; 9: e00782.
12) Takemura T, Ikushima S, Ando T, et al. [Remodeling of the lung in sarcoidosis: a pathological study of 66 autopsy cases], JJSOG. 2003; 23: 43-52.
13) Reed HO, Wang L, Sonett J, et al. Lymphatic impairment leads to pulmonary tertiary lymphoid organ formation and alveolar damage, J Clin Invest. 129 (2019) 2514-26.
14) Lähde S, Jartti A, Broas M, et al. HRCT findings in the lungs of primary care patients with lower respiratory tract infection. Acta Radiol. 2002; 43: 159-63.
15) Aoki T, Nagata Y, Negoro Y, et al. Evaluation of lung injury after three-dimensional conformal stereotactic radiation therapy for solitary lung tumors: CT appearance. Radiology. 2004; 230:101-8.
16) Patterson KC, Strek ME. Pulmonary fibrosis in sarcoidosis. Clinical features and outcomes. Ann Am Thorac Soc. 2013; 10: 362-70.
17) Gurney JW. Cross-sectional physiology of the lung. Radiology. 1991; 178: 1-10.
18) Grunewald J, Grutters JC, Arkema EV, et al. Sarcoidosis. Nat Rev Dis Primers. 2019 Jul 4; 5: 45.
19) Hattori T, Konno S, Shijubo N, et al. Resolution rate of pulmonary sarcoidosis and its related factors in a Japanese population. Respirology. 2017; 22: 1604-8.
20) Judson MA. The treatment of pulmonary sarcoidosis. Respir Med. 2012; 106: 1351-61.