The galaxy sign in pulmonary sarcoidosis.

A 21-year-old woman presented with erythema nodosum, fatigue, diffuse arthralgia and hilar adenopathies visible on the standard chest radiograph. Since the diagnosis of sarcoidosis was considered a CT scan was performed which confirmed the presence of multiple mediastinal and bilateral hilar adenopathies. Additionally, multiple large parenchymal masses in the right upper lobe and in the superior segment of the right lower lobe (Fig. A) were visible.These masses had irregular margins and appeared to represent numerous coalescent micronodules. This radiological finding is described as the "galaxy sign" in which the "galaxy" represents innumerable coalescent granulomatous lesions more concentrated centrally than in its periphery (Fig. B, C). (B: courtesy of Patrick Mergan, Gijzegem, Belgium). Because there were no pulmonary complaints the patient was successfully treated with indomethacin for her inflammatory symptoms. A control CT scan one month later showed spontaneous regression of the mediastinal and hilar adenopathies and a decrease in density of the conglomerates of small nodules. The clinical diagnosis of sarcoidosis was therefore confirmed.