Localized leukemic pulmonary infiltrates. Diagnosis by bronchoscopy and resolution with therapy.

Although commonly found at autopsy, leukemic infiltration of the lung is rarely recognized as a cause of respiratory symptoms or roentgenographic densities. Previously reported cases of patients who had symptomatic or roentgenographic acute leukemic lung diseases invariably presented with diffuse pulmonary infiltrates. We describe three patients with leukemic involvement of the lung who presented with cough, fever, and localized roentgenographic infiltrates suggestive of bacterial pneumonia. In each case, the diagnosis was made by transbronchial biopsy specimen and confirmed by complete response to chemotherapy. In common with the other reported cases, all of our patients had peripheral blast counts above 40 percent (greater than 6,000 blasts per ml3) at the time the pulmonary diagnosis was made. Leukemic invasion of the lung should be considered in patients with acute leukemia who develop lung infiltrates--whether diffuse or focal--in association with a high peripheral blast count.