Pulmonary sarcoidosis: calcification within the galaxy sign.

To cite: Kunal S, Shah A. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2016-218187 DESCRIPTION A 34-year-old woman had breathlessness, dry cough and low-grade fever for 6 months. Chest X-ray showed bilateral hilar lymphadenopathy and patchy alveolar right mid-zone shadows along with bilateral lower zone nodular opacities (figure 1A). Contrast-enhanced high-resolution CT(HRCT) of thorax demonstrated enlarged, non-necrotic right paratracheal, subcarinal and bilateral hilar lymph nodes. The lung window in right upper lobe revealed a large nodule with irregular margins encircled by multiple small nodules suggestive of ‘galaxy’ sign (figure 1B). In addition, mediastinal window divulged dense calcification within the nodule and mediastinal lymphnodes (figure 1C). Fibreoptic bronchoscopy visualised multiple endobronchial granulomatous lesions throughout the tracheobronchial tree (figure 2A) and was confirmed on biopsy (figure 2B). The diagnosis of pulmonary sarcoidosis was based on (1) chest imaging, (2) elevated serum ACE levels (126 IU/mL [8–65 IU/mL]), (3) negative tuberculin test and (4) visible endobronchial lesions and histopathological confirmation of non-caseating granulomas. The ‘galaxy sign’, on HRCT, was first described in sarcoidosis. It refers to a pulmonary nodule, 1–2 cm in size with irregular margins that are surrounded by multiple tiny satellite nodules. This is formed due to the concentration of small nodules, which become less dense towards the periphery causing the perimeter to be irregular. The smaller nodules represent interstitial granulomas. This appearance resembles that of a galaxy hence the name. This sign has now also been documented in pulmonary tuberculosis along with calcification within the nodule. To the best of our knowledge, this is the first documentation of calcification within the nodule suggestive of ‘galaxy sign’ in pulmonary sarcoidosis. Learning points