Chromatin-negative Klinefelter's syndrome with focal megalencephaly.

At autopsy, 72-year-old white male with chromatin-negative Klinefelter's syndrome, mental retardation, psychotic behavior, and carcinoma of the lung was noted to have right unilateral focal cerebral and cerebellar megalencephaly with broad gyri, a cytoarchitectually abnormal cortex, and thickened cerebral vessels. Literature about the neuropathology of Klinefelter's syndrome and several cases of other chromosome aberrations (XYY and XO syndromes) are reviewed. These neuropathological changes are thought to be related to clinical manifestation.