Cystic lung in sarcoidosis: Clinico-radiologic characteristic and evolution.

Background and objective: Sarcoidosis can manifest with atypical findings on chest computed tomography (CT). Cysts are a rare manifestation of lung sarcoidosis. The aim of the study was to describe a series of patients with cystic sarcoidosis and their clinical-radiological characteristics and progression.

Methods: In this retrospective, bicentric study we recruited all patients affected by sarcoidosis with lung cystic lesions at chest CT. We collected clinical characteristics, pulmonary tests and tracked number, distribution and size of the cysts at diagnosis and at the last evaluation.

Results: Twelve patients (6 males, median age 53 years) were identified (prevalence: 1.9%; 95% Confidence Interval: 0.8%-2.9%). All patients presented multiple cystic lesions (median number: 14 [range: 2-216]) with a bilateral distribution in 10/12, micronodules and nodules in 11/12 and fibrotic lesions in 4/12. Seven patients had normal lung function test, three had an obstructive syndrome, one had a restrictive syndrome and one had coexistence of both. During follow-up (median: 10 years [range 1-16 years]), an increase of the number of cysts was observed in four patients. At last evaluation, 3/12 patients experienced a decline of forced vital capacity >10% and 3/12 patients a decline of diffusing capacity for carbon monoxide (DLCO) >10%. A lower DLCO at diagnosis, and the presence of nodules or fibrotic lesions on CT were associated with an increase in the number of cysts.

Conclusion: Cystic lung lesions are rare in patients with sarcoidosis and do not influence long term prognosis.