A 45 year old man presents with a low grade, intermittent fever for 4 weeks, associated with night sweats, loss of appetite and weight loss of 3 kg. He also experienced a mild productive cough, mostly during the day. He denies exposure to gases, fumes or toxic chemicals and is not on any drugs. He denies unsafe sexual encounters and has no history of blood transfusions. He is from a low socioeconomic background. .
There is a heterogeneous opacity in the right upper lobe, with air bronchograms.
HIV serology comes as positive.
The tuberculin test shows an induration of 6 mm after 72 hours.
3 sputum smear specimens are performed, all of which come as negative.