Dermoid (ad-hyoid) cyst at base of tongue. (Marchant.)
Diffuse symmetrical lipoma, multiple. (Lexer.)
In the neck, more often than in any other part of the body, may be seen well-marked cases of diffuse lipoma. These are painless overgrowths of fatty tissue, unencapsulated and consequently liable to spread to an unlimited extent ([Fig. 499]). They form disfiguring clinical pictures, but cause no unpleasant symptoms. They are scarcely to be attacked surgically, as they have no anatomical limit. They are rarely operated. More circumscribed growths can be more or less easily removed.
Of the true tumors of this region little need be said here. There is a form of fibrochondroma, springing from a branchial cleft, which occupies the external orifice of a congenital fistula a little above the clavicular joint. This makes it of interest, and, at the same time, distinctive in character.
Any of these growths may give rise to serious pressure symptoms and may be so located as to make tracheotomy difficult. They often extend downward behind the sternum, in which case the upper part of that bone should be removed in order that they may be safely followed. Such a tumor, if it so extends and is a true cyst, should be treated by free incision and packing; but when solid, no other resource than extirpation is left. On their posterior aspect the greatest caution should be exercised, and it may be well to leave a part of their posterior walls to avoid the danger of injuring the large veins.
The majority of tumors that present on the floor of the mouth which are not of malignant type, nor adenomas of the salivary glands, are embryonic relics, a type alluded to above. A small vestige of this kind may long remain dormant and then suddenly assume a rapid growth.
Of the malignant tumors there are many expressions in the neck of endothelioma, of sarcoma, and of carcinoma, the latter only arising from epithelial structures like those of the skin, the glands, or the mucous membrane. They may extend in all directions. Many cancers of the neck are metastatic, the primary growth not necessarily being in the immediate neighborhood. A distinct form of cancerous degeneration of embryonic vestiges is known under the name of branchiogenic carcinoma. It is seen usually in elderly people and along the line of the branchial clefts. If possible it constitutes a more hopeless variety than others, because of its origin and depth. Certain sarcomas of the neck are prone to assume the type of fungus hematodes. Any tumor of this character should be attacked with spoon and cautery, for the vessels which bleed so easily are only those of the growth itself, those which lead up to it and around its margin not being enlarged.
THE CAROTID BODY.
The carotid body seems to have been first described by Haller, in 1743, although his description has attracted but little attention. In 1833 Mayer recognized that, aside from the well-known cervical ganglia, there was met at the bifurcation of the common carotid a small, so-called glandular structure, about the size of a grain of rice, red, firm, and vascular, much resembling the superior cervical ganglion, which receives sympathetic filaments as well as branches from the vagus. Luschka, in 1862, spoke of it as a glandlike appendage of the sympathetic system in the neck. It is usually wrapped in a sheath from the adventitia of the carotid and perhaps by more or less fat, the former having to be divided before the gland becomes visible. It seems to be a common meeting-place for fibers from the superior laryngeal, the glossopharyngeal, the sympathetic, and certain ganglion nerve fibers. It is not always present and may vary in position, lying either below the division of the artery or considerably above it upon the external carotid. In any case it is enclosed by a sort of capsule.
Its principal surgical interest obtains in that it is the occasional site of tumors, which as they grow will have intimate and perplexing arrangements to the surrounding tissues, which may necessitate most painstaking dissection, or may call for sacrifice of the large vessels. In one case reported by Scudder the tumor became larger and more tender whenever the patient caught cold. Such a tumor will not of itself pulsate, but will transmit pulsation from the carotid in a perplexing manner. They move sidewise, but not vertically. When vascular they may diminish upon pressure, or they may pass in between the other tissues in a way to simulate collapse on pressure. They lie in front of the sternomastoid, above the level of the thyroid cartilage, are usually of slow growth, and are sometimes accompanied by such vasomotor disturbance as flushing of the face and irregularity of the pupil. They are likely to be mistaken for tuberculous lymph nodes, or for common tumors of the neck. While views concerning their absolute malignancy differ, one may be certain that at least they rest upon the border line, and should in all cases be removed. Instances are reported, however, where the tumor has shown an extremely malignant tendency.