Klinefelter syndrome and non-Hodgkin lymphoma.

Patients with a 47,XXY karyotype (Klinefelter syndrome) appear to have an increased risk of developing cancer, especially male breast cancer and germ cell tumors, but rarely malignant hematologic disorders. We report a patient with a low grade B-cell non-Hodgkin lymphoma with a 47,XXY karyotype in both the tumor and constitutional cells. This is only the 13th reported case of malignant lymphoma in a patient with Klinefelter syndrome. Although some authors postulate that the 47,XXY karyotype may be a predisposing factor in the development of hematological malignancies, the lack of reported cases suggests that such associations may be no more than chance findings.