Rapidly progressive cryptogenic organising pneumonia presenting as a lung mass

A very rare case of a rapidly progressive variant of cryptogenic organising pneumonia (COP) presenting as a focal mass-like lesion with compression of the large airways leading to respiratory failure is described. A 60-year-old lady presented to the Aga Khan University Hospital Emergency Department in hypoxaemic respiratory failure with a 6-day history of dyspnoea, productive cough and fever. Chest x ray showed a right upper lobe mass-like lesion compressing the large airways and right pleural effusion. She deteriorated in the Emergency Department and was intubated due to worsening hypoxaemic respiratory failure. The pleural fluid and bronchoscopic specimens were negative on microbiological and cytological examination. CT-guided right lung biopsy revealed chronic non-specific inflammation without granuloma and malignancy. COP was diagnosed on video-assisted thoracoscopic (VATS) lung biopsy. She was successfully treated with high dose steroids and discharged in a stable condition; her 3-month follow-up chest x rays showed complete resolution of the lung lesion with some residual fibrosis.