title: Clinical significance of the "galaxy sign" in patients with pulmonary sarcoidosis in a Japanese single-center cohort.
abstract: BACKGROUND
  The galaxy sign is an irregularly marginated pulmonary nodule formed by a confluence of multiple small nodules, and it is a diagnostic radiological finding for pulmonary sarcoidosis. However, the clinical significance of the galaxy sign for sarcoidosis has been poorly investigated.
  
  
  OBJECTIVE
  This study aimed to investigate the clinical significance and detailed radiological features of the galaxy sign in patients with pulmonary sarcoidosis.
  
  
  METHODS
  We retrospectively reviewed 87 patients with biopsy-proven sarcoidosis and 108 patients with pulmonary tuberculosis. Galaxy sign incidence was assessed on thoracic high-resolution computed tomography (HRCT) images from each group. Correlations of galaxy sign with clinical characteristics and disease outcomes were evaluated for patients with sarcoidosis.
  
  
  RESULTS
  HRCT findings were available for 65 of 87 patients with pulmonary sarcoidosis and all 108 patients with pulmonary tuberculosis. Galaxy sign incidence was significantly higher in patients with pulmonary sarcoidosis (n=15, 23.1%) than in those with pulmonary tuberculosis (n=2, 1.9%, p<0.001). Among the 65 patients with pulmonary sarcoidosis, those with galaxy signs (n=15) were significantly younger (median: 32 years, interquartile range [IQR] 28-38 years) than those without (n=50) (median: 62 years, IQR 37.7-73 years). The CD4/CD8 ratio in bronchoalveolar lavage fluid (BALF) was also significantly lower in the former group (median: 2.6, IQR 2.0-3.9 vs. median 5.8, IQR 3.7-8.6, p<0.001).
  
  
  CONCLUSIONS
  Galaxy signs are associated with younger age and low BALF CD4/CD8 ratio but not disease severity.
authors.affiliation: . sara@yd5.so-net.ne.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Koide
authors.forename: Takeshi
authors.initials: T
authors.lastname: Saraya
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Tsukahara
authors.forename: Francesco
authors.initials: F
authors.lastname: Bonella
authors.forename: Eda
authors.initials: E
authors.lastname: Börner
authors.forename: Manabu
authors.initials: M
authors.lastname: Ishida
authors.forename: Yukari
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hirukawa
authors.forename: Miku
authors.initials: M
authors.lastname: Oda
authors.forename: Masafumi
authors.initials: M
authors.lastname: Shimoda
authors.forename: Kosuke
authors.initials: K
authors.lastname: Ohkuma
authors.forename: Masachika
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Saori
authors.initials: S
authors.lastname: Takata
authors.forename: Takuma
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kurai
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Ishii
authors.forename: Hajime
authors.initials: H
authors.lastname: Goto
authors.forename: Hajime
authors.initials: H
authors.lastname: Takizawa
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D016516:CD4-CD8 Ratio; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007564:Japan; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging* / Q000276:immunology / Q000473:pathology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D017565:Sarcoidosis, Pulmonary / Q000000981:diagnostic imaging* / Q000276:immunology / Q000473:pathology; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D014397:Tuberculosis, Pulmonary / Q000000981:diagnostic imaging* / Q000276:immunology / Q000473:pathology
keywords: Pulmonary sarcoidosis, galaxy sign, clinical significance