Idiopathic hypereosinophilic syndrome progressing to acute myelomonocytic leukemia with chloromas

We have described a patient with idiopathic hypereosinophilia syndrome who progressed to acute myelomonocytic leukemia with chloromas and cerebrospinal fluid involvement with myeloblasts. Four similar cases have been reported in the recent literature. In only one other case of hypereosinophilia and chloromas were myeloblasts demonstrated in the cerebrospinal fluid.