512 Brief Communications

i e ~. ~. ~. ’ Central nervous system involvement characteristically leads to progressive multifocal neurological deficit, dementia, and rapid death.’ Clinical signs of multifocal neurological disease, produced primarily by vascular occlusion, were also present in this cat. However, the marked nuclear pleomorphism and hyperchro-matism, significant mitotic activity, the tendency of the cells to infiltrate vessel walls and the conspicuous skin involvement in the human condition were not a feature of the disease in the cat. Furthermore, the mixture of endothelial cells and pericytes, although seen in other vascular tumors both benign and malignant, is not a feature of neoplastic angioendothe-liosis and suggests the cat was suffering from a different and, as far as we can ascertain, previously unrecorded disorder. The focal intravascular papillary areas observed are remi-niscent of the human condition known as papillary endothe-lial hyperplasia (vegetant intravascular hemangioendothe-lioma or intravascular angiomatosis), a benign generally soli-tary disorder of uncertain etiology. As the names indicate, there is controversy over whether the lesion is neoplastic or reactive ’ and whether the endothelial proliferation could be a sequel of, or prelude to, thrombosis4; certainly such areas in the cat appeared to be associated with the presence of thrombi. Acknowledgement We wish to thank Dr. C. S. Lauer for his interest in this case