A rapidly growing lung mass with air crescent formation

Thorax

Pulmonary puzzle

A 58-year-old man who never smoked and was under follow-up for polymyositis associated with fibrotic interstitial lung disease was found to have an incidental opacity in the right upper lobe on a chest radiograph. He had been treated with daily azathioprine 200 mg and prednisolone 10 mg for 15 years. A CT chest revealed a mass-like lesion of relatively low attenuation suggesting necrosis (figure 1). Bronchoalveolar lavage was negative for microbiology and cytology. CT-guided biopsies were reported as showing necrosis and inflammation only. A month later, he developed cough with malodorous sputum, generalised fatigue, mild fevers, sweats and dyspnoea.

Two months after the first CT, at presentation to our unit, the patient experienced small haemoptyses. Subsequent chest high resolution CT showed a marked increase in size of the lesion and eccentric cavitation (air crescent sign) (figure 2). Bronchoscopic lavage and endobronchial biopsies remained non-diagnostic. Multiple CT-guided...