Congenital cysts of the fourth ventricle : a report of two cases associated with tumor of the optic thalamus and crus cerebri / by J. Ramsay Hunt.

  • Hunt, James Ramsay, 1872-1937.
Date:
1904
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Licence: In copyright

Credit: Congenital cysts of the fourth ventricle : a report of two cases associated with tumor of the optic thalamus and crus cerebri / by J. Ramsay Hunt. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ependyma granulations. A small portion of the cyst wall was cut away, exposing the interior, which was smooth, containing only a small quantity of clear fluid. Microscopic Examination. The medulla, pons, left hemisphere of the cerebellum, and the enclosed cyst were hardened and em- bedded in bulk and cut serially. Approximately every tenth section was prepared and mounted by the Weigert-Pal method; half of these were subjected to a contrast stain (acid-rubrin). Cyst. The cyst begins on a level with the tip of the calamus scriptorius, gradually increasing in size to the plane of the striae acusticae. From this level it becomes smaller and the walls thicker, dipping down into and becoming an integral part of the left side of the pons. On a level with the posterior corpora quadrigemina it terminates as a small triangular cleft, in the neighborhood of the left pyramidal tract. From the tip of the thalamus to the striae acusticae the cyst wall has no connections with the floor of the ventricle, save to the ala pontis (ponticulus) on either side. From the striae acusticae to its termination the cyst wall is intimately associated with the neural structures of the pons. The nerve tracts form a decussation on its under surface, which pass upward into the cyst wall on either side. (Figs. 2, 3, and 4.) The cyst wall may be divided into three layers. An inner one is composed of glia; a thick middle layer of medullated nerve fibres which encircle the wall as a heavy band; and an outer layer in which the network of medullated nerve fibres is sparse, resembling gray matter. No ganglion cells could be demonstrated in the cyst wall, which possessed a rich supply of bloodvessels. No ependyma cells could be demonstrated lining the cyst wall. Here and there flat cells were seen, apparently of epithelial origin. Cerebellum. The vermis and hemispheres of the cerebellum were compressed, and as a result showed changes in their configuration but without atrophy. Medulla and Pons. The left pyramidal tract is small and pale. The lemniscus and fasciculus long, posticus are normal on both sides. The columns of Goll and Burdach are paler than normal, probably due to ascending intramedullary posterior root degenera- tions. (As the cord was not removed this cannot be definitely stated.) The medulla, except for a moderate flattening and lateral elon- gation, maintains its normal configuration to a level with the acoustic nuclei. Here the cyst becomes incorporated with the floor of the ventricle on the left side, nerve fibres decussating on its under surface and passing up into the cyst wall. This decussation is largely formed of the coarse fibres composing the middle peduncles of the pons, and increases considerably as the level of the superior olive is approached. Tegmental fibres, as well as a few fibres from