Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Sarcoidosis (Sarcoid Galaxy sign)
- Radiologic Findings
- Figs 1. Chest PA shows multiple patchy infiltrations in right upper and mid lung zones and bilateral hilar bulging contour.
Fig 2-4. Lung window setting of the chest CT scan shows multiple patchy areas of aggregated tiny nodules including subpleural and peribronchovascular interstitial nodules in RUL and segmental area of peribronchial GGO, fine reticulonodular densities, and nodular consolidation in lateral segment of RML.
Figs 5-6. Mediastinal window setting of the chest CT shows multiple conglomerate lymphadenopathies with relatively homogeneous low attenuation in mediastinum including subcarinal area, both hila, and both interlobar nodal areas.
- Brief Review
- Sarcoidosis is a systemic disorder of unknown cause characterized by the presence of noncaseating granulomas.
Although small parenchymal nodules along the bronchoarterial bundles, interlobular septa, and major fissures and in the subpleural regions are frequently observed in pulmonary sarcoidosis on CT, large nodules (≥1 cm in diameter) are less common.
Sarcoid galaxy sign is the term of characteristic appearance of large parenchymal nodules resembled as galaxy that is a vast collection of millions and occasionally billions of stars. The large parenchymal nodules consisted of numerous small nodules and showed irregular margins. In the periphery of the large nodules, each constituent small nodule had a relatively distinct margin.
Pathologically, the sarcoid galaxy of the large nodule represents innumerable coalescent granulomatous lesions. Toward the center of the sarcoid galaxy, granulomas were much more concentrated than in its periphery. Peripheral low-attenuation spots corresponded to the spaces between partially coalescent small nodules.
- References
- 1. Nakatsu M, Hatabu H, Morikawa K, Uematsu H, Ohno Y, Nishimura K, Nagai S, Izumi T, Konishi J, Itoh H. Large coalescent parenchymal nodules in pulmonary sarcoidosis: "sarcoid galaxy" sign. AJR Am J Roentgenol. 2002;178:1389-1393
- Keywords
- Lung, Mediastinum, Non-infectious inflammation, Sarcoidosis,