History: A 70-year-old woman was admitted with the suspected diagnosis of acute leukaemia. She had complained of decreased physical capacity, nonproductive cough and dyspnoea.
Investigations: The blood picture showed leukocytosis of 46/nl, anaemia (haemoglobin 8.8 g/dl) and thrombocytopenia (25 platelets/nl). Differential white count: 10% blast cells, 43% monocytes. Bone marrow smear revealed acute monocytic leukaemia. The chest radiogram showed increased interstitial markings and lung function tests indicated moderate restriction.
Treatment and course: The atypical pneumonia was treated with erythromycin, but the respiratory functions deteriorated further within 2 days. Cytostatic treatment had been started on the second hospital day, but the patient died a few hours later in respiratory failure. Autopsy revealed numerous alveolar infiltrates by immature myeloid cells.
Conclusion: In patients with acute leukaemia and respiratory symptoms, pulmonary involvement should be included in the differential diagnosis and, if present, chemotherapy immediately begun.