Acute lymphoblastic leukemia. Its occurrence with hypereosinophilic syndrome' and bilateral spontaneous pneumothorax.

A patient with acute lymphoblastic leukemia had an unusual prodrome, including clinical features of "hypereosinophilic syndrome," pulmonary infiltrates, and bilateral spontaneous pneumothorax, which preceded the onset of leukemia by four months. The mechanism for the production of eosinophilia may have been related to the production of eosinopoietic factors by the leukemic cells.