Meningeal Tumours: a Review

Abstract

The tumours to be considered here are those arising primarily in the meninges, or gaining access to them as secondary growths. It will be necessary to consider not only the dura and leptomeninges that invest the brain and spinal cord, but also their extensions into the brain as the tela choroidea and stroma of the choroid plexuses, and the sheaths of the perforating blood-vessels that form the outer boundary of the Virchow-Robin spaces. In the vertebral canal the separation of the dura from the bone by the epidural adipose and areolar tissue, and the resolution of the arachnoid and pia into two distinct membranes, introduce additional factors that are of importance, especially in the direct spread of tumours and the dissemination of their cells by the cerebrospinal fluid.Although little has been heard of it lately, the old controversy as to whether the meninges are of mesodermal or of ectodermal origin cannot be regarded as satisfactorily resolved. In practice, however, it is undisputed that the primary meningeal tumours (meningiomas) display many features in common with mesodermal tumours in other parts of the body; the question of embryological origin is thus purely academic. PRIMARY TUMOURSThe most important group to be considered includes the different varieties of meningioma. Before dealing with these it will be convenient to review a number of rarer tumours, composed of tissues or cells ordinarily foreign to the meninges, which are to be regarded as derivatives of embryonal remnants. These in general mostly occupy the leptomeninges in the mid-sagittal plane over the surface of the brain, though they may be laterally situated. In the vertebral canal they are often associated with congenital malformations, especially spina bifida. Epidermoid and Dermoid CystsThese are not sharply separable as distinct groups. The epidermoid, in which the squamous epithelial lining of the cyst is devoid of skin appendages, is far commoner than the classical dermoid. The best known form is the pearly tumour of Cruveihier, which arises in the leptomeninges as a smooth, often lobulated mass with a characteristic sheen derived from the concentrically laminated exfoliated keratin, mixed with cholesterin, which fills the interior and imparts so brittle a character to the mass. These tumours, which may develop to a considerable size, are usually found at the base of the brain either in the mid-line or in the cerebello-pontine angle; 0 on 28 April 2019 by guest. Protected by copyright.

The diagnostic problem of multiple intracranial tumours—case report of a pituitary chromophobe adenoma and cerebellar haemangioblastoma

“…Russell and Rubinstein (1971) disagree with the suggestion of Casteigne et al (1968) that the stromal cells are of reticulo-endothelial origin and are inclined to accept a pial and vascular origin for such tumours. Considerable pial attachment was demonstrated in our own case which is acknowledged to be a conspicuous feature of cerebellar haemangioblastomas (Russell, 1950).…”

Malignant meningioma metastasizing through the cerebrospinal pathways.

“…Kernohan and Sayre (1952) (Rubinstein, 1972). The progression of the histological pattern of a typical meningioma to that of a spindle-cell sarcoma (Russell, 1950), to an increasingly anaplastic cytological picture (Riley, 1971), or to a papillary pattern (Russell and Rubinstein, 1971) have all been described as identifying a malignant meningioma.…”

“…The occurrence of giant cells with hyperchromatic nuclei does not, however, necessarily convey a sinister significance; on the other hand, that of unusually large numbers of mitotic figures is often indicative of aggressive growth and may herald early recurrence (Rubinstein, 1972). The progression of the histological pattern of a typical meningioma to that of a spindle-cell sarcoma (Russell, 1950), to an increasingly anaplastic cytological picture (Riley, 1971), or to a papillary pattern (Russell and Rubinstein, 1971) have all been described as identifying a malignant meningioma.…”

Pathological and haematological aspects of posterior fossa haemangioblastomata.

“…It may well be that the original hypothesis advanced by Lindau (1926) and Cushing and Bailey (1928) is correct, though it takes no account of haemangioblastomata occurring elsewhere within the neuraxis. The vast majority of haemangioblastomata remain in contact with the pia mater (Russell, 1950) and one might suggest that these other tumours arise by pial invagination of primitive tissues similar to the primordial choroid plexus.…”