A male with Klinefelter Syndrome (KS) is at increased risk for mortality from a number of cancers. Swerdlow et al reviewed epidemiologic data on cancer incidence and mortality in patients with KS. The authors are participants in the UK Clinical Cytogenetics Group and are from multiple hospitals in the United Kingdom.


Increased cancer mortality is seen with:

(1) non-Hodgkin's lymphoma (NHL)

(2) breast cancer

(3) lung cancer


Cancer mortality is decreased for prostate cancer (while the testes of patients with Klinefelter syndrome may be small, the prostate is not).


A patient with KS may be first diagnosed following cytogenetic testing for myelodysplasia, AML or ALL. There does not appear to be an increased risk for these disorders, just increased cytogenetic testing.



(1) A patient with Klinefelter's Syndrome should be strongly encouraged not to smoke or to stop smoking.

(2) A patient with KS who has risk factors for lung cancer should be monitored more closely for lung cancer.

(3) A patient with KS who has gynecomastia or other risk factors for breast cancer should be screened more closely for breast cancer.

(4) The patient should be monitored for evidence of malignancy and instructed to report unexplained fever, night sweats, weight loss and lymphadenopathy.


It would seem prudent to:

(1) minimize radiation exposure, including imaging studies

(2) monitor a patient with KS who is HIV-positive more closely for cancer


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