Association between Klinefelter syndrome and focal nodular hyperplasia.

Focal nodular hyperplasia is a benign lesion of the liver, predominantly affecting women. Its etiology is unknown. Elevated levels of estrogens have been invoked to play a role in the disease. Klinefelter syndrome is the most common sex chromosome disorder, characterized by 47, XXY karyotype, resulting in male hypogonadism and sex hormone imbalance. We present a case of a 25-year-old man affected by Klinefelter syndrome, admitted to our hospital for aspecific dyspeptic symptoms. During admission he underwent: blood test for the liver function and sexual hormonal status, ultrasonography, echo color power Doppler and computerized tomography scan of the liver, and liver biopsy. A hypergonadotropic hypogonadism was present. Imaging of the liver showed an hepatic lesion that liver biopsy confirmed to be a focal nodular hyperplasia. Although the association could be casual, the sex hormone imbalance present in Klinefelter syndrome may suggest a role in the development of this benign liver lesion.