33 Op. cit.
Myxomata are not, histologically, to be distinguished from the gliomatous tissues by anything but the peculiar mucoid changes which their structures have undergone. They are more rare in the brain, as our tables show, than in the spinal cord.
Lipomata are very rare in the brain, according to most observers. The table shows but one example. These tumors, as their name signifies, are made of fat-bearing tissues—another of the connective-tissue class.
The angiomata, somewhat rarely found within the skull, are noted for their abnormal development of the vascular tissues: they are composed mainly of blood-vessels and the connective tissue, which supports them in closely-packed masses. They also present cavernous enlargements. They are of especial interest in cerebral pathology, because the lesion known as pachymeningitis hæmorrhagica, often found in dementia paralytica, is considered by some to be angiomatous; although by far the most generally accepted view of this latter condition is that it is due to arterial degeneration, and in part is an inflammatory exudate.
Syphilitic tumors, or gummata, are, like tubercle, a special development with degeneration from the connective tissue, due to a constitutional taint. This new growth is sometimes single, sometimes multiple. The corpuscles of the neuroglia are the apparent points of origin of the tumor, the substance of which is the firm, peculiarly gummy, and non-juicy material from which the name is derived. It would be impossible in our allowed space to trace this neoplasm through the successive stages of its development. It has especial clinical interest, inasmuch as it and its damage are probably amenable to specific treatment when it has not progressed to too great a destruction of brain-tissue.
The true cancers, or epithelial neoplasms, are not a common form of tumor of either the brain or spinal cord. They present, as in other parts of the body, a stroma forming alveolar spaces in which are contained the nests of epithelial cells. These tumors thus present characteristic differences in their histology from the connective-tissue or mesoblastic groups, but clinically no very special interest attaches to them. Their location, the rapidity of their growth, and their fatal import are points which they share with most other new growths of the cranial cavity.
The cholesteotomata, or pearl cancers, consist of hardened epithelial cells which have undergone a sort of fatty degeneration.
The psammomata are loosely described as tumors containing sand-like bodies, which bodies are normal about the pineal gland. These sand-like bodies are found in tumors of some histological diversity, and do not appear to have much identity of their own. They occur in sarcomata and carcinomata, and are probably not to be distinguished from mere calcareous infiltration and degeneration. They are most common in sarcomata, as this is one of the most common of cerebral tumors.
True osteomata—i.e. tumors with the structure of true bone—are probably rare in the brain, although more common on the inner table of the cranium; but the deposition of calcareous salts has been recorded in a variety of conditions. F. X. Dercum, in a recent paper read before the Philadelphia Pathological Society,34 has recorded the autopsy of a paretic dement in which case calcareous deposits were scattered throughout both hemispheres and the cerebellum. He believes that “the areas in which the concretions were found were probably foci of encephalitis of greater intensity than elsewhere. In these foci inflammatory changes in the walls of the vessels became pronounced; besides which the vessels increased enormously in size and number; so marked is this increase that these foci could, with perfect propriety, be called angiomata.” This is followed by proliferation of the neuroglia, compression and destruction of nerve-tissue, and deposit of the calcareous salts especially about and upon the coats of the vessels. This case illustrates in the simplest manner the formation of both vascular and sand tumors.
34 The Medical News, April 24, 1886, p. 460.