Chronic lymphocytic leukemia with essential thrombocythemia: asbestos exposure association?

We describe a patient with essential thrombocythemia (ET) who developed chronic lymphocytic leukemia (CLL) 10 years after his initial diagnosis. The association of ET and CLL is very rare, and only a handful of cases have been described in the literature. Although the association may be one of chance, some evidence suggests that the 2 neoplasms may be related. Such evidence includes the occurrence of B-cell malignancy and ET in different generations of the same family, with anticipation demonstrated in the pedigree.