Histogenesis of choroid plexus in man

Abstract

Four stages of development can be recognized in the histogenesis of the human telencephalic choroid plexus. Division into stages is based on alterations of outline of the plexus, characteristic appearance and biochemical content of the epithelial cells, and the components of the stroma. The stages are less distinctive in the myelencephalic and diencephalic plexus where differentiation is accomplished sooner than in the telencephalic plexus. Neuroepithelial-lined tubules are common in the choroid plexus, and are formed by folding of choroidal epithelium into the stroma. Some tubules are large enough to be designated as incipient neuroepithelial (colloid) cysts. Cysts having only connective tissue walls are also present. The choroidal epithelial cells proliferate focally, stratify and desquamate into intervillous clefts, or flow into the stroma by disruption of the epithelial basement membrane or tubular wall. These findings are confirmed by use of serial sections. The size of the developing telencephalic plexus relative to the ventricular system is small at first, then large, occupying almost the entire telencephalon, but gradually decreases during development. Glycogen is prominent i n developing choroidal epithelial cells, but disappears in the mature plexus. Both epithelial and mesenchymal mucin and mucopolysaccharides are identified in the plexus. The paraphysis is re-emphasized as an extraventricular choroid plexus on the basis of a common neuroepithelial origin. It is rudimentary and inconstant in man.We have reviewed in another publication the developmental and comparative anatomy of choroid plexus, ependyma and other derivatives of the primitive neuroepithelium in relation to the development of neuroepithelial (colloid) cysts (Shuangshoti, Roberts and Netsky, '65). It was emphasized in that paper that the paraphysis is an extra-ventricular choroid plexus. Because our data indicated a close relationship between the neuroepithelial cyst and the choroid plexus, we decided to study the histogenesis of the choroid plexus in detail. We described in the same paper the finding of mucin and PAS-reactive materials in neuroepithelial cysts and in fragments of choroid plexus attached to the cysts. Histochemical tests for these substances were therefore conducted on developing choroid plexus to clarify these observations. A few investigators have described the times of appearance of the primordia of telencephalic and myelencephalic plexuses in some mammals as in pig (Weed, '17), guinea pig, rabbit and rat (Cohen and Davies, '38; Strong, '56) but the full histogenesis has not been presented. Kiszely AM. J. ANAT., 118: 283-316.

Molecular anatomy and functions of the choroidal blood-cerebrospinal fluid barrier in health and disease

“…The conventional classification, which is still widely used was first described by Shuangshoti and Netsky [136]. It deserves to be completed and nuanced.…”

Scanning electron microscopy study of the choroid plexus in the monkey (Cebus apella apella)

“…Rufos of Ephesus suggested the term "chorioid tunic" to describe the ependyma as the choroid plexus 1 . Later, the choroid plexus was studied at light and electron microscope levels in different animals and by several authors [2][3][4][5][6][7][8][9][10][11][12][13] . The choroid plexus consists of vascular folds from the piamater externally covered by an epithelium derived from the ependimary coating of the ventricles 12 .…”

Third Ventricular Meningioma -Case Report-

“…6,14) The presence of these cells in the choroid plexus has been explained variously. 6,14) The choroid plexus develops initially from an invagination of the mesenchyme in the thin, roof area of the myelencephalon during the 6th week of gestation.…”

“…6,14) The presence of these cells in the choroid plexus has been explained variously. 6,14) The choroid plexus develops initially from an invagination of the mesenchyme in the thin, roof area of the myelencephalon during the 6th week of gestation. 19) In the 7th to 9th weeks, the telencephalic choroid plexus has started to develop a loose mesenchymal stroma, which is covered by a layer of cells derived from the ependyma.…”

“…4) Arachnoid tissue is transported together with the choroid plexus as the ventricular system invaginates, and by 20 to 40 weeks, the central stroma of the choroid plexus contains meningocytes, connective tissues, and blood vessels. 2,14) Meningiomas arise from arachnoid cap cells, which are specialized cells in arachnoid granulations. Similarly, intraventricular meningiomas arise from arachnoid cells contained within the choroid plexus.…”