Pigmented cells in the leptomeninges of the cat.

Cells laden with pigment granules are described in the leptomeningeal tissues of the cat and kitten. These cells can be identified consistently by gross observation following vascular perfusion. The fusiform or stellate pigmented cells are most often found in association with the outermost layers of the arteries of the subarachnoid space. They are typically separated from the cerebrospinal fluid by an attenuated layer of pial cells. Vessels that are described as having pigmented cells along their course are the anterior and posterior cerebellar; the anterior, middle, and posterior cerebral; and the basilar. Electron microscopic studies confirm the presence of abundant pigment granules. The pigment granules are the predominant component of the cytoplasm. Few organelles are demonstrable except for a large central nucleus. The data provide support for the concept of neural crest contribution to leptomeningeal structures. Identification of this isolated, easily defined population of melanocytes may provide a model for further studies of neural crest distribution as well as experimental approaches to melanogenesis and melanoma production and control.