Sézary syndrome with unusual undifferentiated cells.

In this study a case of Sézary syndrome, the Sézary cells showed typical cytoplasmic fibrillar structures, and the nuclei had the characteristic serpiginous appearance. In addition, other unusual undifferentiated cells were found, These cells had round nuclei and few cytoplasmic organelles, and areas of the outer membrane of the nuclear envelope had hairy fine fibrillar projections protruding into the cytoplasm. It is postulated that these cells represent immature Sézary cells, and that as the cells mature, the fibrils become organized around the nucleus, leading to the development of the nuclear deformity.