The most common form of capillary angioma is the nævus or congenital telangiectasis.
Nævus.—A nævus is a collection of dilated capillaries, the afferent arterioles and the efferent venules of which often share in the dilatation. Little is known regarding the etiology of nævi beyond the fact that they are of congenital origin. They often escape notice until the child is some days old, but attention is usually drawn to them within a fortnight of birth. For practical purposes the most useful classification of nævi is into the cutaneous, the subcutaneous, and the mixed forms.
The cutaneous nævus, “mother's mark,” or “port-wine stain,” consists of an aggregation of dilated capillaries in the substance of the skin. On stretching the skin the vessels can be seen to form a fine network, or to run in leashes parallel to one another. A dilated arteriole or a vein winding about among the capillaries may sometimes be detected. These nævi occur on any part of the body, but they are most frequently met with on the face. They may be multiple, and vary greatly in size, some being no bigger than a pin-head, while others cover large areas of the body. In colour they present every tint from purple to brilliant red; in the majority there is a considerable dash of blue, especially in cold weather.
Unlike the other forms of nævi, the cutaneous variety shows little tendency to disappear, and it is especially persistent when associated with overgrowth of the epidermis and of the hairs—nævoid mole.
The treatment of the cutaneous nævus is unsatisfactory, owing to the difficulty of removing the nævus without leaving a scar which is even more disfiguring. Very small nævi may be destroyed by a fine pointed Paquelin thermo-cautery, or by , such as nitric acid. For larger nævi, radium and solidified carbon dioxide (“CO2 snow”) may be used. The extensive port-wine stains so often met with on the face are best left alone.
The subcutaneous nævus is comparatively rare. It constitutes a well-defined, localised tumour, which may possess a distinct capsule, especially when it has ceased to grow or is retrogressing. On section, it presents the appearance of a finely reticulated sponge.
Although it may be noticed at, or within a few days of, birth, a subcutaneous nævus is often overlooked, especially when on a covered part of the body, and may not be discovered till the patient is some years old. It forms a rounded, lobulated swelling, seldom of large size and yielding a sensation like that of a sponge; the skin over it is normal, or may exhibit a bluish tinge, especially in cold weather. In some cases the tumour is diminished by pressing the blood out of it, but slowly fills again when the pressure is relaxed, and it swells up when the child struggles or cries. From a cold abscess it is diagnosed by the history and progress of the swelling and by the absence of fluctuation. When situated over one of the hernial openings, it closely simulates a hernia; and when it occurs in the middle line of the face, head, or back, it may be mistaken for such other congenital conditions as meningocele or spina bifida. When other means fail, the use of an exploring needle clears up the diagnosis.
Mixed Nævus.—As its name indicates, the mixed nævus partakes of the characters of the other two varieties; that is, it is a subcutaneous nævus with involvement of the skin.
It is frequently met with on the face and head, but may occur on any part of the body. It also affects parts covered by mucous membrane, such as the cheek, tongue, and soft palate. The swelling is rounded or lobulated, and projects beyond the level of its surroundings. Sometimes the skin is invaded by the nævoid tissue over the whole extent of the tumour, sometimes only over a limited area. Frequently the margin only is of a bright-red colour, while the skin in the centre resembles a cicatrix. The swelling is reduced by steady pressure, and increases in size and becomes tense when the child cries.
Prognosis.—The rate of growth of the subcutaneous and mixed forms of nævi varies greatly. They sometimes increase rapidly, especially during the first few months of life; after this they usually grow at the same rate as the child, or more slowly. There is a decided tendency to disappearance of these varieties, fully 50 per cent. undergoing natural cure by a process of obliteration, similar to the obliteration of vessels in cicatricial tissue. This usually begins about the period of the first dentition, sometimes at the second dentition, and sometimes at puberty. On the other hand, an increased activity of growth may be shown at these periods. The onset of natural cure is recognised by the tumour becoming firmer and less compressible, and, in the mixed variety, by the colour becoming less bright. Injury, infection, or ulceration of the overlying skin may initiate the curative process.
Towards adult life the spaces in a subcutaneous nævus may become greatly enlarged, leading to the formation of a cavernous angioma.
Treatment.—In view of the frequency with which subcutaneous and mixed nævi disappear spontaneously, interference is only called for when the growth of the tumour is out of proportion to that of the child, or when, from its situation—for example in the vicinity of the eye—any marked increase in its size would render it less amenable to treatment.
The methods of treatment most generally applicable are the use of radium and carbon dioxide snow, igni-puncture, electrolysis, and excision.
For nævi situated on exposed parts, where it is desirable to avoid a scar, the use of radium is to be preferred. The tube of radium is applied at intervals to different parts of the nævus, the duration and frequency of the applications varying with the strength of the emanations and the reaction produced. The object aimed at is to induce obliteration of the nævoid tissue by cicatricial contraction without destroying the overlying skin. Carbon-dioxide snow may be employed in the same manner, but the results are inferior to those obtained by radium.
Igni-puncture consists in making a number of punctures at different parts of the nævus with a fine-pointed thermo-cautery, with the object of starting at each point a process of cicatrisation which extends throughout the nævoid tissue and so obliterates the vessels.
Electrolysis acts by decomposing the blood and tissues into their constituent elements—oxygen and acids appearing at the positive, hydrogen and bases at the negative electrode. These substances and gases being given off in a nascent condition, at once enter into new combinations with anything in the vicinity with which they have a chemical affinity. In the nævus the practical result of this reaction is that at the positive pole nitric acid, and at the negative pole caustic potash, both in a state of minute subdivision, make their appearance. The effect on the tissues around the positive pole, therefore, is equivalent to that of an acid cauterisation, and on those round the negative pole, to an alkaline cauterisation.
As the process is painful, a general anæsthetic is necessary. The current used should be from 20 to 80 milliampères, gradually increasing from zero, without shock; three to six large Bunsen cells give a sufficient current, and no galvanometer is required. Steel needles, insulated with vulcanite to within an eighth of an inch of their points, are the best. Both poles are introduced into the nævus, the positive being kept fixed at one spot, while the negative is moved about so as to produce a number of different tracks of cauterisation. On no account must either pole be allowed to come in contact with the skin, lest a slough be formed. The duration of the sitting is determined by the effect produced, as indicated by the hardening of the tumour, the average duration being from fifteen to twenty minutes. If pallor of the skin appears, it indicates that the needles are too near the surface, or that the blood supply to the integument is being cut off, and is an indication to stop. To cauterise the track and so prevent bleeding, the needles should be slowly withdrawn while the current is flowing. When the skin is reached the current is turned off. The punctures are covered with collodion. Six or eight weeks should be allowed to elapse before repeating the procedure. From two to eight or ten sittings may be necessary, according to the size and character of the nævus.
Excision is to be preferred for nævi of moderate size situated on covered parts of the body, where a scar is of no importance. Its chief advantages over electrolysis are that a single operation is sufficient, and that the cure is speedy and certain. The operation is attended with much less hæmorrhage than might be expected.
Cavernous Angioma.—This form of angioma consists of a series of large blood spaces which are usually derived from the dilatation of the capillaries of a subcutaneous nævus. The spaces come to communicate freely with one another by the disappearance of adjacent capillary walls. While the most common situation is in the subcutaneous tissue, a cavernous angioma is sometimes met with in internal organs. It may appear at any age from early youth to middle life, and is of slow growth and may become stationary. The swelling is rounded or oval, there is no pulsation or bruit, and the tumour is but slightly compressible. The treatment consists in dissecting it out.
Aneurysm by Anastomosis is the name applied to a vascular tumour in which the arteries, veins, and capillaries are all involved. It is met with chiefly on the upper part of the trunk, the neck, and the scalp. It tends gradually to increase in size, and may, after many years, attain an enormous size. The tumour is ill-defined, and varies in consistence. It is pulsatile, and a systolic bruit or a “thrilling” murmur may be heard over it. The chief risk is hæmorrhage from injury or ulceration.
The treatment is conducted on the same lines as for nævus. When electrolysis is employed, it should be directed towards the afferent vessels; and if it fails to arrest the flow through these, it is useless to persist with it. In some cases ligation of the afferent vessels has been successful.
Arterial Angioma or Cirsoid Aneurysm.—This is composed of the enlarged branches of an arterial trunk. It originates in the smaller branches of an artery—usually the temporal—and may spread to the main trunk, and may even involve branches of other trunks with which the affected artery anastomoses.
The condition is probably congenital in origin, though its appearance is frequently preceded by an injury. It almost invariably occurs in the scalp, and is usually met with in adolescent young adults.
The affected vessels slowly increase in size, and become tortuous, with narrowings and dilatations here and there. Grooves and gutters are frequently found in the bone underlying the dilated vessels.
There is a constant loud bruit in the tumour, which greatly troubles the patient and may interfere with sleep. There is no tendency either to natural cure or to rupture, but severe and even fatal hæmorrhage may follow a wound of the dilated vessels.
The condition may be treated by excision or by electrolysis. In excision the hæmorrhage is controlled by an elastic tourniquet applied horizontally round the head, or by ligation of the feeding trunks. In large tumours the bleeding is formidable. In many cases electrolysis is to be preferred, and is performed in the same way as for nævus. The positive pole is placed in the centre of the tumour, while the negative is introduced into the main affluents one after another.