The Pathology of Supratentorial Angiomas

Abstract

HE origin and anatomy of the cerebral angiomas has frustrated pathologists over the years as much as their treatment has baffled surgeons. An extensive literature has developed, replete with picturesque nomenclature based upon attempts to describe the appearance of lesions seen at the operating table or at necropsy. It is believed that no useful purpose would be served now in reviewing these and attempting to explain them in light of present information. The surgical descriptions are not entirely basic nor accurate because the bulk of the lesion is largely submerged under the cortex and hence invisible to the examiner. The pathologic descriptions have been faulty because of deflation of the lesions at the time of examination by lack of the expansile blood stream that characterizes them in life. Also confusing the picture of the dead lesion are the alterations produced in the component vessels by blood under arterial pressure, which dilates veins and arterializes them to withstand the added stress. Vascular resistance being lowered by the shunt, arteries dilate to carry more blood under less than usual pressure, and lose some of their usual characteristics. Histologically the lesions appear only as a tremendously convoluted mass of arteries, veins and intermediate types of vessels of extremely variable diameters traversing cerebral tissues altered in structure by the intervening and now deflated vessels. CLASSIFICATION Cushing and Bailey 2 were able to separate the intraeranial blood-vessel tumors into two principal groups, a) the hemangioblastomas, truly neoplastic masses confined chiefly to the posterior fossa, and b) the largely supratentorial group composed of blood vessels contained within cerebral tissue. We are concerned with the latter group. Cushing and Bailey divided these into a) telangiectases, b) venous angiomas and e) arterial (arteriovenous) angiomas. Again, it is with the latter two groups that we are concerned. Oliveerona and Riives 9 agreed with Cushing and Bailey that these are histologically inseparable; the difference is physiologic and depends upon the degree of arterialization of the lesion. Upon the advent of angiography it became apparent that earlier expressed suspicions against the existence of purely venous angiomas were well grounded; in all reported cases the