To cite: Biswas A, Patel V, Jantz M, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2015211391 DESCRIPTION A 44-year-old woman with HIV (non-compliant to therapy), atypical mycobacterial infection and pneumocystis infection in the past, presented with subacute fever of 5-day duration. She also had a cough with productive yellow sputum that gradually turned into a dry cough. Physical examination was consistent with bilateral rhonchi and wheezes. She was an ex-smoker who had quit 10 years earlier, but was a current cocaine and cannabis abuser. Chest X-ray showed airway opacities on the right middle zone suggestive of pneumonia (figure 1). A CT scan of the chest showed scattered right middle lobe nodular opacities (figure 2). Differential diagnosis included Pneumocystis jiroveci pneumonia, tuberculosis, non-tuberculosis mycobacterial infection and fungal infections such as histoplasmosis, cryptococcosis, blastomycosis and lymphoma. The patient’s clinical, radiographic and histopathology was consistent with respiratory bronchiolitisassociated interstitial lung disease (RB-ILD). Bronchoscopy revealed a normal airway, however, the bronchoalveolar lavage fluid was black in colour (figure 3). Transbronchial biopsies were also black. Histopathology revealed extensive intra-alveolar pigment laden macrophages and type 2 pneumocyte hyperplasia devoid of granulomas, eosinophils, malignancy or infection (figure 4). RB-ILD is a type of idiopathic interstitial pneumonia that is classified as a smoking-related lung disease having the pathological features of respiratory bronchiolitis, clinical symptoms of cough and dyspnoea; high-resolution CT usually shows diffuse