Galaxy sign (lungs)
Galaxy sign
(lungs) • Globular cluster M92 in Hercules: photograph - Ganzer Fall bei Radiopaedia
Galaxy sign
(lungs) • Galaxy sign of sarcoidosis - Ganzer Fall bei Radiopaedia
Galaxy sign
(lungs) • Tuberculosis - multisystem involvement - Ganzer Fall bei Radiopaedia
Galaxy sign
(lungs) • Thoracic sarcoidosis - Ganzer Fall bei Radiopaedia
Galaxy sign
(lungs) • Miliary tuberculosis with spondylitis - Ganzer Fall bei Radiopaedia
The so-called galaxy sign, initially described as the sarcoid galaxy, represents a coalescent granuloma seen in a minority of patients with pulmonary sarcoidosis . The same appearance can be seen in tuberculosis . In other words, it represents a mass-like region composed of numerous smaller granulomas. The appearance of a central core with peripheral nodules is reminiscent of a globular cluster or galaxy.
Central cavitation does occur and the lesions may be surrounded by ground-glass opacity . The latter is thought to represent extensive interstitial sarcoid granulomas below the resolution of HRCT rather than alveolitis or hemorrhage .