Thorax 1982;37:554-555 The air crescent sign of invasive pulmonary aspergillosis in acute leukaemia

The radiographe appearance of an air crescent surround-ing a dense opacity is classically associated with pulmonary aspergilloma in patients with pre-existing lung disease such as healed tuberculous cavities. ' We describe three patients with previously normal chest radiographs who developed air crescents as a manifestation of invasive pulmonary aspergillosis complicating acute leukaemia. In a further patient, who died of disseminated aspergillosis, an appear-ance mimicking pulmonary aspergilloma was found at nec-ropsy. To our knowledge only 12 similar cases have been reported,2-5 and in none was tomography performed to aid diagnosis. Case reports Four patients with acute leukaemia developed invasive pulmonary aspergillosis during remission-induction chemotherapy (table). Each patient had had a normal chest radiograph before receiving cytotoxic chemotherapy. All four patients developed localised homogeneous shadowing on their chest radiographs while neutropenic. Broad-spectrum antibiotic treatment was started but the radiographic changes progressed, and in three patients single or multiple air crescents appeared within the pulmo-nary shadowing during the following three weeks (fig). In one patient (case 4) tomography showed air crescent for-mation before the sign became apparent on plain radio-graphy one week later. One patient (case 1) failed to achieve remission of leukaemia, and died before the cause of the pulmonary shadowing could be established. No antifungal treatment was given to this patient. At necropsy both upper lobe