Acute cerebellar hemorrhage in a patient with Klinefelter syndrome: XXY karyotype obtained postmortem from cells from pericardial fluid.

A case of Klinefelter syndrome and a spontaneous cerebellar hemorrhage in a 12-year-old boy is presented. Autopsy revealed that the hemorrhage was due to the rupture of a dilated artery in an arteriovenous malformation in the right cerebellar hemisphere. The small, undescended testes exhibited partial atrophy of the seminiferous tubules. Postmortem chromosome analysis of cells from the pericardial fluid demonstrated a 47, XXY karyotype. He had previous surgical treatment for bilateral thumb polydactyly and patent ductus arteriosus. In juvenile cases of sudden death with overlapping morphological dysgenesis, postmortem karyotyping may provide important diagnostic information.