The high frequency of pulmonary complications of haematological malignancy and the increasing number of patients treated for these disorders make it important that the respiratory physician has a structured diagnostic approach according to: 1 the immune deficiency due to the malignancy and/or the treatment administered; 2 the factors that can modify the risk of infection (anti infection prophylaxis and/or pre-emptive treatment); 3 co- morbidities; 4 extra-pulmonary manifestations.

Two main situations can be identified: The patient is aplasic: Initially the pneumonias are predominantly of bacterial origin but may be fungal if the neutropenia is prolonged. The respiratory physician is faced with two problems: 1 the diagnosis of pneumonia; this may be helped by CT scanning; 2 The choice of antibiotics; this will depend on previous investigations. The patient is not aplasic: The lung disease may have many causes, mainly infectious but also drug related, tumoral, haemorrhagic or embolic. The main problem is the correct choice of investigations to establish an aetiological diagnosis.

The collection of data according to a pre-established protocol based on simple factors (study of the notes and clinical examination) is one of the key elements for improving the prognosis of these patients whose management should be multidisciplinary following a pre-defined plan.