Malignant tumors are common about the scalp and the cranium; they assume, however, no conventional appearance, and are seen in any shape or form, those of the scalp alone occurring either as carcinoma or epithelioma from its epithelial elements, or as sarcoma from its mesoblastic elements. Tumors primary in the periosteum or bone are necessarily of sarcomatous nature, while those of the type which perforate to the surface may be either sarcoma or possibly endothelioma. The general character of these growths has been referred to previously. In regard to their extirpation (for there is no other treatment than this) operations of varying degrees of severity may be required. (See [Cysts and Tumors] and [Tumors of Bone].)
Fig. 367
Osteosarcoma of the temporal region. Metastatic tumor in the arm and thyroid. (Parker.)
The superficial epithelioma should be attacked before it has become adherent, in which case everything should be removed down to the underlying periosteum, after which a plastic operation will permit the repair of the defect, so that primary union of the whole surface may be secured. Any malignant growth which is adherent to the underlying cranial bone calls not only for removal of its own substance, but for that of the bone to which it is attached. To fail in this is to invite recurrence. This may necessitate more or less extensive osteoplastic resections of the bone, but the condition permits of no middle course. Extensive resections of bone have been made with success, and need not be abstained from unless there be good reason to fear involvement of the dura or cortex. In this case the advantages and dangers should be carefully weighed before proceeding to operation. During operations on the bone great care should be taken, especially in certain regions, to avoid injury to the intracranial sinuses, although it has been learned that these may be ligated and intervening portions removed. But the wounding of the sinus by the point of an instrument or spicule of bone may lead to a hazardous and annoying complication, and is to be prevented when possible. A small wound in a sinus may be plugged with gauze, which may remain for two or three days. There is always a possibility of air embolism (see [pp. 38] and [363]) when the sinuses are opened, as their walls do not easily collapse. Hemorrhage from the soft parts may be almost entirely controlled by the use of an elastic tourniquet stretched around the skull. Oozing veins in the diploë or in the bone may often be secured by pressing the tables of the skull together with bone forceps, while at other times an antiseptic wax can be forced into the interstices of the bone and hemorrhage thus checked. In certain cases where it seems impracticable to slide flaps and cover defects the desired end may be obtained by skin grafts, after Thiersch’s method.
A rare and specialized form of blood tumor, seen only on or within the cranium, is the so-called hernial dilatation of the superior longitudinal sinus. It may present through openings in the bone; sometimes pressure upon it will cause vertigo and perhaps greater prominence of adjoining veins, even of the jugulars.
NON INFLAMMATORY DISEASES AND CONGENITAL CONDITIONS OF THE SKULL.
Incomplete Formation of Bone (Aplasia Cranii).
—Incomplete formation of bone is occasionally met with. The bone is a secondary formation in the skull, the dura and skin being originally in contact; consequently this condition can be easily explained as a failure to develop bone where it is normally produced. These defects are most common in the frontal and temporal regions. The bone may fail also to develop to ordinary thickness, and may be found as thin as paper or ossifying only in certain directions. Supernumerary bones may also develop, apparently to take the place of those previously lacking. Aplasia may also be a unilateral defect and contribute toward the formation of meningocele. Atrophy or anostosis—i. e., complete disappearance of cranial bones—is occasionally observed. It may be an interstitial or an eccentric process, and may happen at any point or at several spots. Up to a certain extent it is the rule in the skulls of the aged, when the bones become reduced to the thinness of paper or may in certain places completely disappear. Senile atrophy, in other words, is a normal process, and is to be expected after the sixtieth year of life, its possibility being not forgotten when operations are undertaken upon the skulls of those advanced in years. Eccentric atrophy may also occur from pressure of soft or hard tumors, among them the so-called Pacchionian bodies. It is also stated that increasing hydrocephalus may produce an internal and eccentric anostosis.