Manual of Surgery Volume I Part 22

This form is therefore most frequently met with on the face and neck in the situations which correspond to the various clefts and fissures of the embryo. It occurs also on the trunk in situations where the lateral halves of the body coalesce during development. Such a dermoid usually takes the form of a globular cyst, the wall of which consists of skin, and the contents of turbid fluid containing desquamated epithelium, fat droplets, cholestrol crystals, and detached hairs. Delicate hairs may also be found projecting from the epithelial lining of the cyst.

Faulty coalescence of the cutaneous covering of the back occurs most frequently over the lower sacral vertebrae, giving rise to small congenital recesses, known as post-a.n.a.l dimples and coccygeal sinuses.

These recesses are lined with skin, which is furnished with hairs, sebaceous and sweat glands. If the external orifice becomes occluded, there results a dermoid cyst.

_Tubulo-dermoids_ arise from embryonic ducts and pa.s.sages that are normally obliterated at birth, for example, _lingual dermoids_ develop in relation to the thyreo-glossal duct; _rectal and post-rectal_ dermoids to the post-a.n.a.l gut; and _branchial dermoids_ in relation to the branchial clefts. Tubulo-dermoids present the same structure as skin dermoids, save that mucous membrane takes the place of skin in the wall of the cyst, and the contents consist of the pent-up secretion of mucous glands.

_Clinical Features._--Although dermoids are of congenital origin, they are rarely evident at birth, and may not give rise to visible tumours until p.u.b.erty, when the skin and its appendages become more active, or not till adult life. Superficial dermoids, such as those met with at the outer angle of the orbit, form rounded, definitely limited tumours over which the skin is freely movable. They are usually adherent to the deeper parts, and when situated over the skull may be lodged in a depression or actual gap in the bone. Sometimes the cyst becomes infected and suppurates, and finally ruptures on the surface. This may lead to a natural cure, or a persistent sinus may form. Dermoids more deeply placed, such as those within the thorax, or those situated between the r.e.c.t.u.m and sacrum, give rise to difficulty in diagnosis, even with the help of the X-rays, and their nature is seldom recognised until the escape of the contents--particularly hairs--supplies the clue.

The literature of dermoid cysts is full of accounts of puzzling tumours met with in all sorts of situations.

The treatment is to remove the cyst. When it is impossible to remove the whole of the lining membrane by dissection, the portion that is left should be destroyed with the cautery.

_Ovarian Dermoids._--Dermoids are not uncommon in the ovary (Fig. 59).

They usually take the form of unilocular or multilocular cysts, the wall of which contains skin, mucous membrane, hair follicles, sebaceous, sweat, and mucous glands, nails, teeth, nipples, and mammary glands. The cavity of the cyst usually contains a pultaceous mixture of shed epithelium, fluid fat, and hair. If the cyst ruptures, the epithelial elements are diffused over the peritoneum, and may give rise to secondary dermoids.

[Ill.u.s.tration: FIG. 59.--Dermoid Cyst of Ovary showing Teeth in its interior.]

The ovarian dermoid appears clinically as an abdominal or pelvic tumour provided with a pedicle; if the pedicle becomes twisted, the tumour undergoes strangulation, an event which is attended with urgent symptoms, not unlike those of strangulated hernia.

The treatment consists in removing the tumour by laparotomy.

#Teratoma.#--A teratoma is believed to result from partial dichotomy or cleavage of the trunk axis of the embryo, and is found exclusively in connection with the skull and vertebral column. It may take the form of a monstrosity such as conjoined twins or a parasitic ftus, but more commonly it is met with as an irregularly shaped tumour, usually growing from the sacrum. On dissection, such a tumour is found to contain a curious mixture of tissues--bones, skin, and portions of viscera, such as the intestine or liver. The question of the removal of the tumour requires to be considered in relation to the conditions present in each individual case.

CYSTS[3]

[3] Cysts which form in relation to new-growths have been considered with tumours.

Cysts are rounded sacs, the wall being composed of fibrous tissue lined by epithelium or endothelium; the contents are fluid or semi-solid, and vary in character according to the tissue in which the cyst has originated.

_Retention and Exudation Cysts._--_Retention cysts_ develop when the duct of a secreting gland is partly obstructed; the secretion acc.u.mulates, and the gland and its duct become distended into a cyst.

They are met with in the mamma and in the salivary glands. Sebaceous cysts or wens are described with diseases of the skin. _Exudation cysts_ arise from the distension of cavities which are not provided with excretory ducts, such as those in the thyreoid.

_Implantation cysts_ are caused by the accidental transference of portions of the epidermis into the underlying connective tissue, as may occur in wounds by needles, awls, forks, or thorns. The implanted epidermis proliferates and forms a small cyst. They are met with chiefly on the palmar aspect of the fingers, and vary in size from a split pea to a cherry. The treatment consists in removing them by dissection.

_Parasitic cysts_ are produced by the growth within the tissues of cyst-forming parasites, the best known being the taenia echinococcus, which gives rise to the _hydatid cyst_. The liver is by far the most common site of hydatid cysts in the human subject.

With regard to the further life-history of hydatids, the living elements of the cyst may die and degenerate, or the cyst may increase in size until it ruptures. As a result of pyogenic infection the cyst may be converted into an abscess.

The _clinical features_ of hydatids vary so much with their situation and size, that they are best discussed with the individual organs. In general it may be said that there is a slow formation of a globular, elastic, fluctuating, painless swelling. Fluctuation is detected when the cyst approaches the surface, and it is then also that percussion may elicit the "hydatid thrill" or fremitus. This thrill is not often obtainable, and in any case is not pathognomonic of hydatids, as it may be elicited in ascites and in other abdominal cysts. Pressure of the cyst upon adjacent structures, and the occurrence of suppuration, are attended with characteristic clinical features.

The _diagnosis_ of hydatids will be considered with the individual organs. The disease is more common in certain parts of Australia and in Shetland and Iceland than in countries where the a.s.sociation of dogs in the domestic life of the inhabitants is less intimate. Pfeiler, who has worked at the _serum diagnosis of hydatid disease_, regards the complement deviation method as the most reliable; he believes that a positive reaction may almost be regarded as absolutely diagnostic of an echinococcal lesion.

The _treatment_ is to excise the cyst completely, or to inject into it a 1 per cent. solution of formalin. In operating upon hydatids the utmost care must be taken to avoid leakage of the contents of the cyst, as these may readily disseminate the infection.

A _blood cyst_ or haematoma results from the encapsulation of extravasated blood in the tissues, from haemorrhage taking place into a preformed cyst, or from the saccular pouching of a varicose vein.

A _lymph cyst_ usually results from a contusion in which the skin is forcibly displaced from the subjacent tissues, and lymph vessels are thereby torn across. The cyst is usually situated between the skin and fascia, and contains clear or blood-stained serum. At first it is lax and fluctuates readily, later it becomes larger and more tense. The treatment consists in drawing off the contents through a hollow needle and applying firm pressure. Apart from injury, lymph cysts are met with as the result of the distension of lymph s.p.a.ces and vessels (_lymphangiectasis_); and in lymphangiomas, of which the best-known example is the cystic hygroma or hydrocele of the neck.

GANGLION

This term is applied to a cyst filled with a clear colourless jelly or colloid material, met with in the vicinity of a joint or tendon sheath.

The commonest variety--the _carpal ganglion_--popularly known as a sprained sinew--is met with as a smooth, rounded, or oval swelling on the dorsal aspect of the carpus, usually towards its radial side (Fig. 60).

It is situated over one of the intercarpal or other joints in this region, and may be connected with one or other of the extensor tendons.

The skin and fascia are movable over the cyst. The cyst varies in size from a pea to a pigeon's egg, and usually attains its maximum size within a few months and then remains stationary. It becomes tense and prominent when the hand is flexed towards the palm. Its appearance is usually ascribed to some strain of the wrist--for example, in girls learning gymnastics. It may cause no symptoms or it may interfere with the use of the hand, especially in grasping movements and when the hand is dorsiflexed. In girls it may give rise to pain which shoots up the arm. Ganglia are also met with on the dorsum of the metacarpus and on the palmar aspect of the wrist.

[Ill.u.s.tration: FIG. 60.--Carpal Ganglion in a woman aet. 25.]

The _tarsal ganglion_ is situated on the dorsum of the foot over one or other of the intertarsal joints. It is usually smaller, flatter, and more tense than that met with over the wrist, so that it is sometimes mistaken for a bony tumour. It rarely causes symptoms, unless so situated as to be pressed upon by the boot.

_Ganglia in the region of the knee_ are usually situated over the interval between the femur and tibia, most often on the lateral aspect of the joint in front of the tendon of the biceps (Fig. 61). The swelling, which may attain the size of half a walnut, is tense and hard when the knee is extended, and becomes softer and more prominent when it is flexed. They are met with in young adults who follow laborious occupations or who indulge in athletics, and they cause stiffness, discomfort, and impairment of the use of the limb. A ganglion is sometimes met with on the median aspect of the head of the metatarsal bone of the great toe and may be the cause of considerable suffering; it is indistinguishable from the thickened and enlarged bursa so commonly present in this situation in the condition known as bunion.

[Ill.u.s.tration: FIG. 61.--Ganglion on lateral aspect of Knee in a young woman.]

Ganglionic cysts are met with in other situations than those mentioned, but they are so rare as not to require separate description.

Ganglia are to be diagnosed by their situation and physical characters; enlarged bursae, synovial cysts, and new-growths are the swellings most likely to be mistaken for them. The diagnosis is sometimes only cleared up by withdrawing the clear, jelly-like contents through a hollow needle.

_Pathological Anatomy._--The wall of the cyst is composed of fibrous tissue closely adherent to or fused with the surrounding tissues, so that it cannot be sh.e.l.led out. There is no endothelial lining, and the fibrous tissue of the wall is in immediate contact with the colloid material in the interior, which appears to be derived by a process of degeneration from the surrounding connective tissue. In the region of the knee the ganglion is usually multilocular, and consists of a meshwork of fibrous tissue, the meshes of which are occupied by colloid material.

It is often stated that a ganglion originates from a hernial protrusion of the synovial membrane of a joint or tendon sheath. We have not been able to demonstrate any communication between the cavity of the cyst and that of an adjacent tendon sheath or joint. It is possible, however, that the cyst may originate from a minute portion of synovial membrane being protruded and strangulated so that it becomes disconnected from that to which it originally belonged; it may then degenerate and give rise to colloid material, which acc.u.mulates and forms a cyst. Ledderhose and others regard ganglia as entirely new formations in the peri-articular tissues, resulting from colloid degeneration of the fibrous tissue of the capsular ligament, occurring at first in numerous small areas which later coalesce. Ganglia are probably, therefore, of the nature of degeneration cysts arising in the capsule of joints, in tendons, and in their sheaths.

_Treatment._--A ganglion can usually be got rid of by a modification of the old-fashioned seton. The skin and cyst wall are transfixed by a stout needle carrying a double thread of silkworm gut; some of the colourless jelly escapes from the punctures; the ends of the thread are tied and cut short, and a dressing is applied. A week later the threads are removed and the minute punctures are sealed with collodion. The action of the threads is to convert the cyst wall into granulation tissue, which undergoes the usual conversion into scar tissue. If the cyst re-forms, it should be removed by open dissection under local anaesthesia. Puncture with a tenotomy knife and sc.r.a.ping the interior, and the injection of irritants, are alternative, but less satisfactory, methods of treatment.

_Ganglia_ in the substance of _tendons_ are rare. The diagnosis rests on the observation that the small tumour is cystic, and that it follows the movements of the tendon. The cyst is at first multiple, but the part.i.tions disappear, and the s.p.a.ces are thrown into one. The tendon is so weakened that it readily ruptures. The best treatment is to resect the affected segment of tendon.

The so-called "compound palmar ganglion" is a tuberculous disease of the tendon sheaths, and is described with diseases of tendon sheaths.

CHAPTER XI

INJURIES

CONTUSIONS--WOUNDS: _Varieties_--WOUNDS BY FIREARMS AND EXPLOSIVES: _Pistol-shot wounds_; _Wounds by sporting guns_; _Wounds by rifle bullets_; _Wounds received in warfare_; _Sh.e.l.l wounds_. _Embedded foreign bodies_--BURNS AND SCALDS--INJURIES PRODUCED BY ELECTRICITY: _X-ray and radium_; _Electrical burns_; _Lightning stroke_.

CONTUSIONS

A contusion or bruise is a laceration of the subcutaneous soft tissues, without solution of continuity of the skin. When the integument gives way at the same time, a _contused-wound_ results. Bruising occurs when force is applied to a part by means of a blunt object, whether as a direct blow, a crush, or a grazing form of violence. If the force acts at right angles to the part, it tends to produce localised lesions which extend deeply; while, if it acts obliquely, it gives rise to lesions which are more diffuse, but comparatively superficial. It is well to remember that those who suffer from scurvy, or haemophilia (bleeders), and fat and anaemic females, are liable to be bruised by comparatively trivial injuries.

_Clinical Features._--The less severe forms of contusion are a.s.sociated with _ecchymosis_, numerous minute and discrete punctate haemorrhages being scattered through the superficial layers of the skin, which is slightly dematous. The effused blood is soon reabsorbed.

The more severe forms are attended with _extravasation_, the extravasated blood being widely diffused through the cellular tissue of the part, especially where this is loose and lax, as in the region of the orbit, the s.c.r.o.t.u.m and perineum, and on the chest wall. A blue or bluish-black discoloration occurs in patches, varying in size and depth with the degree of force which produced the injury, and in shape with the instrument employed. It is most intense in regions where the skin is naturally thin and pigmented. In parts where the extravasated blood is only separated from the oxygen of the air by a thin layer of epidermis or by a mucous membrane, it retains its bright arterial colour. These points are often well ill.u.s.trated in cases of black eye, where the blood effused under the conjunctiva is bright red, while that in the eyelids is almost black. In severe contusions a.s.sociated with great tension of the skin--for example, over the front of the tibia or around the ankle--blisters often form on the surface and const.i.tute a possible avenue of infection. When deeply situated, the blood tends to spread along the lines of least resistance, partly under the influence of gravity, pa.s.sing under fasciae, between muscles, along the sheaths of vessels, or in connective-tissue s.p.a.ces, so that it may only reach the surface after some time, and at a considerable distance from the seat of injury. This fact is sometimes of importance in diagnosis, as, for example, in certain fractures of the base of the skull, where discoloration appears under the conjunctiva or behind the mastoid process some days after the accident.

Blood extravasated deeply in the tissues gives rise to a firm, resistant, doughy swelling, in which there may be elicited on deep palpation a peculiar sensation, not unlike the crepitus of fracture.