Nuclear structures of primary malignant lymphoma in the brain.

Abstract

Various classes of nuclear granules and inclusion bodies were observed in primary malignant lymphoma cells in the brain. In addition to the chromatin and the nucleoli, the perichromatin granules and the unusual dense granules were main granular structures. However, the most prominent features were clusters of interchromatin granules. The individual interchromatin granules were round or ovoid, sometimes filamentous in shape, and about 30 to 40 mμ in diameter. They were not extractable in enzyme digestion with pepsin, RNAase, or DNAase, and decreased markedly in electron density when both pepsin and RNAase were employed. It may be reasonably assumed that the interchromatin granules may be a complex of RNA and acidic proteins. Some nuclear bodies involved the interchromatin granules in formation. This study may suggest 2 possible processes of formation of nuclear bodies, which are derived (a) from the interchromatin substances or (b) from the inner nuclear membranes.