A Structural Study of Ossification and Calcification in Meningiomas

Abstract

In meningiomas of the convex surface of the cerebrum which have also infiltrated the dura, peculiar transformations of diploe’s spongy tissue and spicule like formations are regularly produced on the internal as well as the external tables of the skull. These structural changes in the diploe are even more clearly evident after mazeration preparation of the bone (Fig. 1). In none of our cases have we been able to prove a purely reactive hyperostosis due to a presumably strong increase, in blood circulation but without a direct tumor invasion. It would be wrong, judging from these macroscopic pictures, to assume that a pure destruction of the skull by infiltration of meningioma tissue was taking place. Histologically and microradiographically, that is, through X-rays of bone cuts, we see clear signs of bone formation as well as degeneration. Newly formed bone tissue whose mineral content is in part incomplete is found boardering the tumor (Fig. 2). In the osteocyte lacunae lie osteocytes rich in cytoplasm with a large nucleus and sometimes vacuols. The small canals of threads of osteocytes can be clearly seen in colored thinly sliced bone sections. We do not see oesteclasts, so we must assume that osteolysis of the osteocytes has occured (2, 3). The meeting of such destructive events in juxtaposition shows a very dynamic bone renovation. Obviously, the osteocyte is capable of bringing about bone formation as well as deterioration.