Though of small size, and not possessed of malignant action or disposition, is a tumour of very great interest, on account of the excruciating pain with which it is accompanied. It is mostly situated in the subcutaneous cellular tissue, but not unfrequently in the intermuscular cellular substance; one tumour of this species which I have removed was so deep as to be in immediate contact with the sheath of the posterior tibial nerve. The tumour, generally of the size of a garden pea, rarely exceeds that of a cherry. It is invested by a dense ligamentous cyst, to which it intimately adheres; but occasionally the capsule is thin and cellular: in many instances its surface is perfectly smooth, in others it is slightly nodulated. It is not connected with any large nervous trunk; but minute nervous fibrillæ can occasionally be traced expanding on its surface, and apparently entering its substance. Internally it is composed of numerous whitish fibres, of considerable density, ramifying irregularly throughout its structure; and betwixt these is insinuated a firm substance, generally of a grey colour, and frequently of an almost cartilaginous consistence. Such is the structure most frequently observed; but in this morbid formation, as in all others, the appearances may be said to vary in almost every instance. Sometimes the fibres are indistinct, and of a yellowish or dirty grey colour; and the interfibrous matter is often found to vary in density and colour in different tumours, being at one time dense and almost transparent, at another opaque and cartilaginous, and sometimes rather soft, brownish, and occasionally tinged with blood. From attentive examination, it appears extremely probable that the enlargement is at first produced by infiltration of lymph betwixt the fibrillæ of a nervous twig, which becomes separated and inclosed by the deposit—that they afterwards increase in size—that the interfibrous matter is deposited in greater quantity, and is farther condensed—and that thereby the nervous filaments are still more separated and extenuated. In short, it would appear that the fibrous matter is nervous, though altered, and that the interposed substance is organised and condensed lymph. The tumour, at first extremely minute, enlarges slowly; when deep, it can only be obscurely felt, and its existence is with difficulty discovered by manipulation; but the attending symptoms are so peculiar, and so forcibly developed, as to lead the surgeon at once to an accurate diagnosis. When it is subcutaneous, the skin is rendered slightly prominent, and the size, density, and loose connections of the growth, are readily ascertained. The slightest pressure causes the most excruciating torments, and totally unmans the patient, even though induced by the most trifling movement of the adjoining muscles. From a fearful and well-grounded knowledge of this circumstance, the patient is extremely anxious to preserve the limb in a state of complete rest, and, in fact, he is often wholly unable to use it; although the part is completely set at rest, still he frequently suffers from paroxysms of severe pain, commencing in the tumour and shooting through the limb. The painful sensations are sometimes very much alleviated by gentle friction with the hand. The disease is most frequent in the extremities, and in the inferior more than in the superior.
The larger nervous trunks sometimes become diseased, being affected with an enlargement resembling the structure and appearance of the preceding tumour, and such enlargements are termed Neuromata. Occasionally a portion of a nervous trunk is thus enlarged, from a blow or wound; and sometimes there can be no cause assigned. Nerves when divided, become bulbous on that extremity towards their centre. In stumps this is well seen; whilst all the tissues entering into it, after a time shrink, and become more or less atrophied (bone, muscles, vessels, &c.), the extremities of the nerves swell out and present a bulbous appearance. When these tumours are connected to, and only covered by, integument, or when they are adherent to the ligamentous substance covering the bone, and become exposed to pressure, as in badly made stumps, the patient often suffers excruciating agony. The nervous trunk above is, in general, slightly enlarged, sometimes has a tortuous course; and in some instances the neurilemmal bloodvessels are considerably increased in size. The same symptoms exist, though in a less acute form, as in the painful tubercle.
OF POLYPUS.
A common species of tumour is that which is attached to a mucous surface, and is called POLYPUS. Polypi vary in structure and disposition; some are simple and benign, others are most malignant. The simple mucous polypus has a shining appearance, being invested by an extremely delicate membrane, in some degree resembling the mucous, and moistened by a fluid similar to the mucous secretion; it is of soft consistence and homogeneous structure. They are generally light brown, sometimes greyish, and in some degree diaphanous. They are connected to the mucous membrane by a narrow pedicle; generally occur in clusters, and are of pyriform shape; one or more are often suspended from one narrow base, and they seldom attain a large size. They possess but little vascularity, though occasionally minute vessels are seen ramifying pretty freely on their surface, and may be considered as almost devoid of sensibility. The malignant polypus, on the contrary, is always attached to the mucous membrane, and also to the subjacent parts, by means of a broad base; and its form and structure vary according to the particular action which it has assumed. Most frequently it is encephaloid, of an irregular form, and often presenting a cauliflower appearance, its surface being studded with numerous excrescences of medullary consistence and colour. Such tumours will be afterwards treated of, as occurring in different situations.
OF ENCYSTED TUMOURS.
Along with these have been classed the enlargements of bursæ, sheaths of tendons, &c., but with equal propriety might we include hydrocele and other collections in natural cavities. Encysted tumours are almost always situated superficially. The skin is distended, seldom inflamed, and often contains enlarged bloodvessels, which give it a streaked appearance. They consist of an external cyst, which is in some instances extremely thin and delicate, in others dense, of considerable thickness, and composed of fibrous looking substance, occasionally it is almost cartilaginous; the internal structure may be said to be almost always more or less fluid, but varies much in consistence. The tumour is surrounded with condensed cellular substance, which is of greater or less thickness and strength according to the size of the tumour. Some of these tumours are supposed, and on good grounds, to be mere enlargements of the natural mucous follicles, in consequence of obstruction in their ducts, by hardened and vitiated secretion; the cyst, therefore, will be at first thin and delicate; its contents will resemble the natural secretion of the follicle, and in many cases may be readily squeezed out. There is a black point on the most prominent part, marking the obstructed orifice of the follicle, and the sac is found at this point to adhere firmly to the skin. Even after all other marks of its original formation have disappeared, the situation of the orifice is sometimes indicated by small dark spots, by depression, or by a minute ulcer.
Encysted tumours, or wens, as they have been called, often appear to be hereditary; seldom occur single, and are met with under the surface of all parts of the body. They have been divided into different classes, according to the nature of their contents: Atheromatous; containing curdy matter; Meliceritous, containing a substance like
honey; and Steatomatous, containing fatty matter, generally in a semifluid condition. But such terms are not adequate to express the nature of all encysted tumours; they are extremely various in their actions, and their contents vary according to the particular secretory action which the lining membrane of the cyst assumes; for the same reason, also, the contents of a tumour will differ in the different stages of its progress. Some contain a thin, fetid, brown fluid, mixed with solid particles, resembling half-dissolved fibrinous matter; in some the contents are serous, or sero-purulent,—in others they are gelatinous; whilst in those which have become inflamed from external irritation, the contents are altogether purulent, or contain a very considerable proportion of that fluid; not unfrequently the cyst is covered internally by a layer of calcareous matter, to which similar particles are loosely attached. Sometimes, in consequence of irritation, organisable matter is poured out on the inner surface of the cyst, adheres firmly to its inner surface, and is often disposed in concentric laminæ.
Sometimes, though rarely, the most prominent parts of the tumour ulcerate, and on the exposed surface is deposited a substance of semifluid consistence and gelatinous appearance, which afterwards increases in density, and ultimately assumes all the characters of horn. This hard excrescence in some instances increases only to a slight degree, and afterwards remains stationary; in others it attains a large size, and occasionally assumes a curved or tortuous form, like that of the horns of inferior animals. Horns are generally met with on the forehead, and the scalp may be said to be their seat. The largest which I have seen, measured seven inches in length, and two in circumference; but others have been removed still larger.