A Non-Aspergillosis Cause of Air Crescent Sign

A 65 old man, with a history of heavy smoking was diagnosed with pulmonary adenocarcinoma. The initial chest CT showed a solid mass in the upper left lobe (Figure 1). Post-chemotherapy chest CT revealed a cavitary lesion with an air-crescent sign (Figure 2). The resulting aspect is an expression of the necrotic excavation of the tumor.