抄録
Among the variety of meningiomas, the so-called “angioblastic meningiomas” originally described by Harvey Cushing and his associates have been controversial in terms of their exact cytogenesis. The most recent WHO classification has dropped the term “angioblastic meningioma” but compromized it by including three additional subtypes of meningiomas, i.e., angiomatous, hemangiopericytic, and hemangioblastic, so as to perpetuate the traditional notion that they are of meningeal origin. In the authors' experience with over 200 cases of meningiomas, four types of histologically and cytogenetically distinct neoplasms which would potentially be called or have actually been called “angioblastic meningioma” by unwary pathologists have been recognized. They are: 1) meningiomas with abundant vascular stroma in which the meningeal tumor parenchyma was obscured; 2) intracranial hemangiopericytomas which were histologically identical to those arising outside of the central nervous system; 3) extra-cerebellar hemangioblastomas, especially those located in the supratentorial regions, which were histologically identical to those of the cerebellar primary but found in patients with no stigmata of von Hippel-Lindau disease; and 4) benign hemangioendotheliomas which were often attached to the dural tissue. Except for the first type, all of these neoplasms are apparently originated from the cellular elements of blood vessel and should not be classified as any type of meningiomas. The distinct histological characteristics of these four types of tumors were described in detail, and their clinical features were discussed. It is emphasized that the term “angioblastic meningioma” should be abandoned and that hemangiopericytoma, hemangioblastoma, and hemangioendothelioma should be recognized as separate entities among the neoplasms of blood vessel origin within the central nervous system, and not as subtypes of meningiomas with prefixed adjectives.
