Klinefelter's syndrome and acute leukemia.

Klinefelter's syndrome is associated with an increased risk of certain types of cancer. A small number of reports have documented the occurrence of acute leukemia in these patients. Our review of 1200 consecutive patients investigated cytogenetically for actual or suspected hematologic malignancy revealed only one patient with acute leukemia and the 47,XXY syndrome. This finding suggests that the risk of acute leukemia in Klinefelter's patients is no greater than that of the general population.