Cytology of the Normal and Abnormal Choroid Plexi in Selected Domestic Mammals, Wildlife Species, and Man

Abstract

Abstract.A cytologic study of the choroid plexi of animals and humans was carried out using impression smears (imprints, imp) to understand better the cellular changes that occur in the cerebrospinal fluid in the case of disease. The samples, totaling 756 imp were from 11 dogs (239 imp), 10 horses (219 imp), 1 mule (23 imp), 3 cattle (69 imp), 1 sheep (19 imp), 2 pigs (39 imp), 1 deer (20 imp), 4 monkeys (22 imp), and 7 humans (106 imp). The samples came from individuals clinically free of neurologic disease, as well as from a few abnormal cases. Six of the 7 humans had no history of neurologic disease and had a complete necropsy with brain histopathology. The seventh human case had mild neurologic signs at the time of death and only a partial necropsy with histopathological examination of the brain, in which a few small leptomeningeal lymphocytic infiltrates and polymicrogyria were found. One of the human brains without neurologic disease had arteriosclerosis. In the 40 individuals studied, several features and some unique cell types were found, for which little or no information is available. Four different morphologic cell types were consistently found in all the species studied. The first 3 types were arbitrarily named alpha (with deeply basophilic cytoplasm), beta (with neutral to weakly acidophilic cytoplasm), and gamma or vesicle-bearing cells. The third type, gamma, was a cell bearing unique inclusions (vesicles) filled with many tiny light tan to pale pink granules. The fourth type was the Kolmer cell found in very low numbers. Immature lymphocytes were found in all of 3 newborn foals, in 1 pig, and in the only stillborn calf and deer studied. The results suggest that the choroid plexi contain more than 1 epithelial cell type and that knowledge of their morphology is far from complete because other unusual cells and structures are also present in small numbers. Imprints are excellent for studying the choroid plexi, especially for tiny changes that are too subtle to be seen in hematoxylin and eosin sections.The first cytologic specimens of human cerebrospinal fluid (CSF) were studied for diagnostic purposes more than a century ago. 25 Subsequently, the cytologic study of the CSF has become routine procedure in human and veterinary hospitals all over the world. Because about 90% of the CSF is produced by the choroid plexi cells (ChPCs), 22 knowledge of the appearance of these cells in cytologic specimens can be useful for the identification of cells or structures found in the CSF. Considerable confusion exists, however, on the actual morphology of ChPCs in CSF specimens, for although a few publications have illustrated their incidental finding in the CSF, no proof of their identity has ever been offered. On comparing the photographs of purported ChPCs depicted in 5 different cytology publications, none of them shows the same cell type, and no proof of their identity is offered. 4,5,15 Also, the ASCP official publication on the cytology of body fluids does not even include a photograph. 14 Surprisingly, no...

Molecular and pathological investigations of the central nervous system inBorrelia burgdorferi–infected dogs

“…In other species, small numbers of lymphocytes have been described in the choroid plexus. 9 Though a similar finding has not been reported in dogs, it is logical to assume that a small number of inflammatory cells would be expected within the choroid plexus of young dogs, and this concurs with the authors' personal observations. Choroid plexitis is a potential lesion that could be associated with the neurological signs previously reported in dogs with Lyme disease.…”

Nonlesions, Unusual Cell Types, and Postmortem Artifacts in the Central Nervous System of Domestic Animals

“…25). The cytoplasm frequently contains tiny vacuoles, 38 and electron microscopy reveals long cellular processes (Fig. 26).…”