Chapter XXXVIII

, is, nevertheless, practically a cyst of congenital

origin involving the spinal meninges. One form of spina bifida is constituted by cystic dilatation of the central canal of the spinal cord, and produces _syringomyelocele_. These conditions will be treated more fully in their appropriate places.

Sutton has rendered a great service by showing that the brain and spinal cord are evolved from a segment of the primary intestines, and that the _intestinal canal and the neural canal communicate in fetal life_ at their _lower terminations_; while it has been shown by several that in the earlier forms of mammalian life they were also connected by their _anterior terminations_. It is in this way that certain complex tumors of the sacral and coccygeal region are to be explained. So also is the collection of lymphoid tissue in the vault of the pharynx, known as _Luschka’s tonsil_, and in the coccygeal region, known as _Luschka’s gland_, it being a curious and instructive fact that lymphoid tissue of this character is always met with in the neighborhood of obsolete canals.

=Hydatid Cysts.=--These cysts are the indirect product of the eggs of the Tænia echinococcus, a form of tape-worm which infests the alimentary canal of dogs. The eggs reach in some direct or indirect way the food or water taken into the human stomach and are there hatched; the young animals migrate through vessel walls and are deposited in some tissue or organ where the cyst later develops. These cysts have a thick, elastic wall, with a lining containing cells, involuntary muscle fibers, and a water-vascular system. After such a cyst has attained the size of an inch or more, small vesicles, or “brood capsules,” begin to develop, which present at one point a retractable head, with scolices so arranged in crown form as to produce sucking disks. According to the date at which the cyst is opened appearances will differ. Sometimes a large cavity will be filled with multiple “daughter cysts,” and sometimes these will have disappeared, so that the cyst fluid contains nothing distinctive. After having ceased to develop, hydatids frequently undergo atrophy and even become calcified; the characteristic hooklets are the last of the distinctive features to disappear.

These growths may be rapid, even to the point of producing necrosis and rupture, or may be very slow and persist almost unchanged for years. The disease is uncommon among the native-born population of the United States, and most of its examples are seen in emigrants. It is exceedingly prevalent in Iceland and in New Zealand. It occurs most often in the liver, but is frequently met with in these countries in the lungs, the brain and spinal canal, and the bones, but may be encountered in any part of the body. When located near the intestinal tract or the air tract the cysts are more liable to penetration by ordinary germs of sepsis, and then may suppurate. It is not infrequent to have conversion of an hydatid cyst into an abscess. Before or after such change it may undergo rupture, spontaneous or traumatic, and this, according to the nature and amount of its contents, and the location of the opening, will promptly produce more or less grave symptoms. While spontaneous recovery has, in rare instances, followed rupture, it has perhaps more often led to fatal result. At all events, it will produce serious and perhaps distressing symptoms.

The only radical treatment for hydatid cysts is extirpation. When this is not possible the cyst may be opened and the margins of the opening attached to those of the skin wound. After being evacuated it should be packed and drained, and then may be expected to slowly contract, perhaps even to the point of obliteration. The contents of such a cyst should not be allowed to escape into any of the body cavities, since their sterility can not be always relied upon.

=Cystic Degeneration.=--_Hematocele_ is an expression meaning a tumor composed originally of effused blood which has undergone chemical and other changes, which consist of lamination and thickening of its exterior portion and fluidification of the interior, until in course of time such an internal blood clot may be converted into a distinct and plainly walled cyst. This condition may be seen in two locations--namely, in the _pelvis_ and _between the cranium and the brain_, or in the brain. The hemoglobin gradually disappears, and the contents of these cysts are translucent or even watery in appearance. Hematoceles may form where there has been internal hemorrhage in certain locations which has failed to absorb, and where no pyogenic infection has occurred.

Pseudocystic changes occur in other tumors and in other parts of the body as the result of _mucoid_ and _colloid liquefactions_. In the midst even of apparently dense and entirely defined tumor masses changes of this kind occur, and lead to formation of cavities containing fluid of variable consistence, causing the tumor when divided to present the appearance of the geodes or quartz rocks, containing cavities lined with quartz crystals. The occurrence of such cystic changes is indicated, in naming such a tumor, by prefixing the term _cysto-_, as cystosarcoma, cystofibroma, etc.

2. =Dermoids.=

Dermoids are _cysts or tumors containing tissues and appendages which are developed from the epiblast_, and which occur when skin and mucous membrane are not normally found. The simplest form of dermoid is a cyst whose interior is lined with modified skin, containing sebaceous glands and hair follicles, from which often numerous long hairs are produced. Even sweat glands may be present. Its cavity is occupied by mixed material, pultaceous in character, made up of sebum, cholesterine, and growing hairs which are often rolled into balls. The sebum is the product of the glands contained in the cyst wall.

A complex form of so-called dermoid cyst is met with in which there are unstriped muscle fiber, teeth, mammary glands, etc. These belong rather to the class of teratomas, as they contain more or less tissue not of epiblastic origin.

A _dermoid tumor_ is one lacking cystic characteristics, made up of tissue largely developed from the epiblast, with more or less tissue of mesoblastic origin. Such a tumor may contain much connective tissue, fat, fetal hyaline cartilage, and nerve tissue, while from its exterior long hair may grow, and teeth project from its surface or be embedded within its substance. Such tumors are generally found in the pharynx and about the rectum.

The explanation of dermoids and teratomas may be gleaned from embryology, and rests upon the arrangement of the different blastodermic layers of the developing ovum, and upon the facts already alluded to in explaining Cohnheim’s hypothesis of the origin of tumors. Strictly speaking, a _dermoid_ should contain only that which may be developed from the _epiblastic_ layer. It is well known that teeth and hair, as well as sebaceous material, are epiblastic products. Consequently such material may be found within a dermoid and needs no further explanation than an epiblastic inclusion, according to Cohnheim’s views. But so soon as such a tumor contains bone, muscle, etc. (_i. e._, tissues of mesoblastic origin), we should drop the term _dermoid_ and consider it a _teratoma_. Such is the distinction between these two terms. According to Wilm’s researches, any tumor of this sort which contains epithelial products as teeth or hair is sure to contain also mesoblastic elements, and thus to belong to the latter. The term _epidermoids_ has been applied to the former.

The most prominent characteristics of dermoid cysts are: (1) _Skin_, which may be thick or thin, lined with papillæ, containing more or less pigment, its deeper layers possessing a quantity of fat. (2) _Hair_, which next to skin is the most constant structure found in dermoids; this may be present in trifling amount or in long coils or balls. It is of interest that in dermoids found in animals covered with wool we find the same character of hairy structure, while in birds dermoids contain feathers rather than hairs. (3) _Sebaceous glands_ and their peculiar secretion are invariably found. These may be of large size, and sebaceous retention cysts may be seen in the walls of dermoids. Sometimes _horny_ matter or tissue is found in these, indicating the same relation between horn and sebaceous structures, as we see upon the external skin in other instances. So, too, material resembling the texture of finger-nails is occasionally found projecting into the cavity.

The fluid or semifluid contents of these cysts consist usually of sebaceous material, cholesterin, epithelial debris, etc. Sometimes it is thick, sometimes thin--and occasionally consists almost entirely of mucus.

It is not uncommon to find structures in _ovarian_ dermoids closely analogous to, or actually resembling, _mammary glands_. These may be mere nipple-like processes of skin, or completely developed _mammæ_, well formed, but without ducts or gland tissue, may occupy such a cyst. These really are _pseudomammæ_, because they have no ducts. Nevertheless, glandular tissue is not always absent. This resemblance proceeds even farther, in that in some of these ovarian mammæ changes occur analogous to those which take place in normal breasts.

The epiblast seems to have the power of developing mammary glands or supernumerary mammæ in many locations--in fact, upon any part of the body surface. About the thorax they are common; upon the abdomen they are rarely observed; and they have been found even upon the labia.

_Sweat glands_ are infrequent in dermoids. _Teeth_ are quite common. These may vary in number from two or three up to several hundred--may be embedded in definite sockets or simply sprout from the cyst wall. Occasionally bone material, lodging such teeth and crudely resembling a jaw, will be found.

Dermoids containing _mucous membrane_ are found, especially in connection with the ovary and with the postanal gut (_i. e._, the original communication between the spinal and alimentary canals).

It is curious that under these circumstances mucous membrane is sometimes furnished with hair, as it normally is in the stomach or other cavities of some of the lower animals. Mucous glands and retention cysts of these glands are also found in ovarian dermoids. This will be more readily understood if the mutability of skin and mucous membrane be not forgotten. The transition from one to the other is not difficult, and we find all intermediate stages between the two extremes--if not in man, at least in animals. This will account for the fact that skin-covered dermoid tumors are found in certain parts of the alimentary canal, and particularly in the pharynx. These tumors grow also from the mucous membrane of the bowel, of the rectum, or even of the small intestine.

Sutton has made a division of dermoids into three classes:

1. _Sequestration_;

2. _Tubulodermoids_;

3. _Ovarian_.

1. =Sequestration Dermoids.=--Sequestration dermoids occur chiefly in situations where during embryonic life coalescence takes place between two surfaces possessing an epiblastic covering, although sometimes this coalescence practically occurs late in life and by implantation.

Dermoids of the trunk occur particularly where opposite halves of the body wall coalesce--that is, in the midline of the trunk and head. Dermoid cysts are rarely found in connection with _spina bifida_, and certain tumors spoken of as spina bifida undoubtedly are dermoids. Anteriorly dermoids occur frequently in the scrotum, and occasionally in the testicle. At the umbilicus they are rarely found--usually as pedunculated tumors projecting externally. In the midline of the thorax and neck they are most common opposite the manubrium, dropping down behind it to invade the anterior mediastinum. Near the hyoid bone they occur relatively frequently; about the head they are met with most commonly at the angles of the orbits--more so at the outer than at the inner angle. Dermoid cysts are known to oculists as growing upon the iris or springing from the conjunctiva. About the ear they are not infrequent; in the roof of the mouth, especially if this be incomplete, we frequently find cysts of epiblastic origin.

Sequestration dermoid cysts are also undoubtedly found in connection with the _dura mater_, in the scalp, most commonly at the anterior fontanelle, at the root of the nose, and at the external occipital protuberance, where they may be confounded with sebaceous cysts or with meningoceles. In order that a dermoid of the dura may communicate with the skin there must of course be osseous defect.

Sequestration dermoids upon the limbs have been mostly reported as sebaceous cysts. They are rare, and usually associated with antecedent injury, by which epiblastic structures are driven in and implanted in such a way that as they develop they give rise to these peculiar tumors. These are what Sutton calls _implantation dermoids_. They are found upon the fingers and elsewhere.

2. =Tubulodermoids.=--These are largely connected with obsolete canals and ducts. It is a great service which Sutton has rendered in proving, apparently beyond the possibility of doubt, that the central canal of the nervous system is really of intestinal origin, and may be regarded as a disused segment of the primary alimentary canal. He has also shown how it behaves occasionally as do other functionless ducts, and that cysts and dermoids in connection with it are to be thus explained. He and others have also shown the anterior as well as the posterior communication of these canals, and the pituitary body are to be regarded in this light as the same formation of lymphoid tissue around an obsolete canal which we see in Luschka’s tonsil close by, and in Luschka’s gland at the other extreme of the canal.

[Illustration: FIG. 72

Solid dermoid escaping from pelvis. (Original.)]

[Illustration: FIG. 73

Congenital dermoid cyst of pelvis. (Ahlfeld.)]

The primary alimentary canal was a continuous tube lined with a continuous layer of columnar epithelium. That portion connected with the yolk sac develops into the intestine, the balance into the central nervous canal. Portions of this canal are in postnatal life absolutely obsolete; others persist in a rudimentary condition. Dermoid cysts and dermoid tumors develop in connection with each of these. In some there is a large central cavity; others are almost absolutely solid. Thus we find dermoids in the coccygeal region, which have been variously regarded as sarcomas, adenomas, etc., which are really of origin as stated above and should be considered simply as dermoid tumors. Most of these project outwardly; some of them arise and develop within the pelvis. Dermoid cysts and tumors are also met with in connection with the rectum--sometimes between the rectum and the bladder, and between the rectum and the spine. Dermoid tumors are also found in connection with the pituitary body. These sometimes develop within the cranium, or, again, protrude perhaps into the orbit, perhaps into the pharynx.

_Thyroid dermoids_ are tumors of great interest. They develop sometimes about the craniopharyngeal canal, which may be detected as a small canal in the macerated sphenoid bone of a fetus, and which before birth is filled with fibrous tissue. It connects with a recess in the middle line and at the base of the skull, presenting in the pharynx, which is often referred to as the _bursa pharyngea_. It is around this recess that the lymphoid tissue known as the “pharyngeal tonsil” develops. It may be thus expected that the roof of the pharynx should be the occasional site of dermoids. It is from the pharynx or the floor of the mouth that in vertebrates the thyroid body arises. In higher forms it becomes dissociated from the pharynx and shifts its position. The thyroid body is developed around the thyroid duct, which first appears as the thyrohyoid duct, which later becomes divided, that portion in relation with the tongue becoming the thyrolingual duct, the remaining portion persisting as the thyroid duct. These are present about once in every ten subjects, according to Sutton, the canal when persistent being lined with epithelium. When the extremities of these ducts become occluded retention cysts may form. In the same way dermoids of the tongue are formed, similar to those occurring on the scalp. These are frequently mistaken for sebaceous cysts. They may be unilateral, central, or even bilateral. The _lingual_ duct is also of interest, because it would appear that certain cases of epithelioma of the tongue arise along this duct, and perforating malignant ulcer of the tongue is thus produced. Dermoid tumors of the lingual or thyroid ducts resemble in structure the thyroid body. The thyroid duct may also be detected in many adults running from the isthmus of the thyroid body to the posterior aspect of the hyoid bone, and surrounded by muscle tissue. Sometimes the space usually occupied by this duct is represented by a series of detached bodies known as _accessory thyroids_. These are not infrequently the seat of cysts, sometimes of considerable size. (The accessory thyroids often enlarge when the main thyroid has been extirpated for disease.) Thus cysts in close relation to the hyoid bone are common. Some of them grow slowly, while others grow rapidly and contain much fluid. Many of them are unilateral, and are often mistaken for enlargements of one lobe of the thyroid. Cysts growing from accessory thyroids are often filled with papillomatous masses, and are occasionally the seat of malignant degeneration.

In the _omphalomesenteric_ duct or its remains, especially in relation with the umbilicus, we often meet with small cysts or tumors in infants and young children. When the duct is persistent it presents normal intestinal structure, and, like the appendix, possesses much adenoid or lymphoid tissue.

Another and very important form of _tubulodermoids_ develops in connection with the _branchial clefts_ of the neck. Congenital fistulas of the neck have been long known, but only comparatively recently understood. Of the branchial clefts it is well known that the first alone should persist, as the Eustachian tube. Occasionally, however, they fail to become obliterated, and then we have congenital tumors or cysts, which may, perhaps, not develop to appreciable size until somewhat late in life; or there may be fistulous passages opening either into the pharynx or externally, forming canals varying in length from half an inch to two inches, secreting a little fluid because lined with epithelium. When these become inflamed an abscess results. When they open externally the opening is often marked by a little tag of skin containing a fragment of yellow cartilage. These are often referred to as _cervical auricles_. They open along the line of the sternomastoid muscle. The internal openings of these fistulas frequently form diverticula from the pharynx or esophagus. Thus it will be seen that dermoid cysts about the neck are principally relics of openings or ducts, which are normal in embryonic life, but which should have been obliterated at or long before birth. Congenital fistulas, however, may be met with in the middle line of the neck, which are not to be confounded with branchial fistulas, but rather with the ducts previously described.

3. =Ovarian Dermoids and Teratomas.=--These may be unilocular or multilocular cysts, usually the latter. They are lined with epithelium, and contain mostly mucoid fluid, the inner coat being practically identical with mucous membrane. Occasionally, however, the skin is furnished with hair, sebaceous glands, teeth, and even nipples. The multilocular cysts are practically an aggregation of those just described. They are surrounded by dense capsules, often attain great dimensions, and are made up of primary cysts resembling large cavities in a honeycomb-like mass, which itself is occupied by secondary cysts, and belong rather to the class of mucous retention cysts, these being occupied by still smaller ones, which are histologically indistinguishable from distended ovarian follicles. In these large tumors we find in some cases hair, in others teeth, and in others sebaceous glands, etc., the dermoid constituents being scattered throughout. As Wilms has shown, in almost every tumor of this character a projection may be found whose summit is covered with epiblastic elements, which when cut in serial transverse sections will show in its deeper portion other epithelial collections representing a feeble attempt to develop a nervous system, or lung tissue, while mesoblastic elements, like connective tissue, cartilage, and bone, appear scattered throughout, as though a very crude effort had been made to reproduce an atypical embryo.

3. =Teratomas.=

So far the endeavor has been to limit the term _dermoid_ to tumors which are essentially of _epiblastic_ formation, their location being explained on the inclusion theory of Cohnheim. There is also a still more complicated type of tumor, composed of tissues of both _epiblastic and mesoblastic_ origin, perhaps even _hypoblastic_. Their consideration belongs to that department of pathology known as _teratology_, which is supposed to deal especially with monsters. Strictly speaking a _teratoma_ refers to an irregular tumor or mass containing tissues and fragments of viscera of a suppressed fetus which is attached to an otherwise normal individual. Nevertheless the term is often applied to growths which are the result of luxuriant mesoblastic development in which neither form nor member of a suppressed fetus is present.

The presence of supernumerary members is largely connected with what is called _dichotomy_, alluding thereby to cleavage either at the anterior or posterior end of the developing embryo. _When the whole embryonic axis divides twins may be produced_, but should cleavage be

## partial we may have a monster with two heads if it be anterior, or

one with three or more limbs if it be posterior. Children born with these deformities are usually called _monsters_, and the study of such cases belongs entirely to teratology. But in certain tumors small portions of a suppressed fetus may develop, as, for instance, from the posterior portion of the sacrum, or within the abdomen or thorax, or upon the neck or face, which on dissection may contain a few vertebrae or processes resembling fingers associated perhaps with a structure resembling intestine or liver. This should be called a teratoma. Such tumors possess for the pathologist the greatest value. In surgery, however, they are rare, and there are scarcely two cases alike. The question of operation will often arise, as it does with supernumerary limbs, and each case should be studied upon its own merits. Sometimes they are amenable to extirpation.

=Embryonal Adenosarcoma.=--Embryonal adenosarcoma is a term given to certain teratomatous tumors peculiar to renal and adrenal structure, which present peculiar characteristics in the mixture of elements which enter into their composition. At various times these tumors have been called adenoma, sarcoma, rhabdomyoma, congenital cystic kidney, etc. They have been also likened to the thyroid. They comprise a group of neoplasms, always congenital in origin, which usually appear early in life, but occasionally occur in advanced adult life. One of the most marked specimens of this kind the writer removed from a man over fifty years of age. Most of the specimens, however, described in literature pertain to the young. On minute examination they often present a strange, mixed picture of voluntary muscle elements intermingled with epithelium arranged to imitate acinous glands, with cystic dilatations of the true kidney tissue. They often attain enormous size, and undergo such proliferation of mesoblastic elements as to resemble sarcoma. Their occurrence is to be explained only on the principles of Cohnheim’s hypothesis. When the original Wolffian body is being differentiated from the elements about it a confusion of the same with the excretory tubular beginnings, which are to empty into the Wolffian duct, occurs. Thus we have the commencement of a mixed mass which presents itself as a more or less rapidly growing tumor, in which even cartilage or other mesoblastic structures may be met with. It is scarcely possible that any two specimens should yield exactly the same microscopic picture, much depending on whether one element or the other prevail. In a few of them there may occur also a mixture of adrenal elements. Sometimes the renal structure itself is more or less distinct, and rides, as it were, upon the surface of the tumor; at other times it is entirely mixed up with it. While the condition is usually limited to one side it may be a double affection, so that the second kidney becomes useless and the patient succumbs. The only treatment is extirpation.

Teratomatous tumors are sometimes found hanging in the pharynx, attached by a small pedicle, where they may be confounded with dermoids unless carefully examined after removal. Many instances of this type of tumor are found in animals. Here no false sentiment will prevent complete examination and preservation of the specimen. They are also encountered in the sacral and coccygeal regions.

4. =Tumors of Connective-tissue Type.=

=Lipoma.=--Lipomas, or tumors composed of fat, are the most common of the neoplasms. Their normal type is the _ordinary adipose tissue_ of the body, and may be divided into the _encapsulated_ and the _diffuse_, the former of which are surrounded by fibrous tissue. The diffuse lipomas are those which have no capsule, and where the pathological collection of fat merges into that normally present--in other words, they are not circumscribed.

=Subcutaneous Lipomas.=--Subcutaneous lipomas are perhaps the most common of all, and are usually irregularly lobulated and encapsulated, adherent rather to the skin than to the deeper tissues. Usually but one is found in an individual, though instances of multiple lipomas are not rare. They develop sometimes to enormous size, cases being on record where the tumor has even weighed one hundred pounds. They may be met with at any point on the surface of the body. The lobules often burrow between the muscles, and those found in the palm of the hand penetrate even beneath the palmar fasciæ. They are sometimes markedly pedunculated, and often hang by a small stem. The diffuse subcutaneous lipoma is most common about the neck, in the groin, and in the axilla.

=Subserous Lipomas.=--Subserous lipomas are mostly retroperitoneal, and large tumors of this character, mistaken for ovarian, have been successfully removed by operation. They also occur in the hernial canals and spaces. They develop beneath the peritoneum covering the intestines, and in this location give rise occasionally to _intussusception_. Here in their pathological development they have the general form and significance of _appendices epiploicæ_.

=Subsynovial Lipomas.=--Subsynovial lipomas occur about various joints and tendon sheaths; within the knee they assume a distinctive type which has been called _lipoma arborescens_, where they take on a dendritic appearance and arrangement. _Submucous_ lipomas are rare. _Intermuscular_ fatty tumors are occasionally met with, an interesting variety being that which develops between the masseter and buccinator muscles. _Intramuscular_ forms rarely occur, as well as a variety known as _parosteal_, which arises in connection with the periosteum. Fatty tumors also occur within the spinal dura, as well as outside of it within the spinal canal, and more or less lipomatous alterations are common in connection with spina bifida.

Lipomas are ordinarily easy of recognition, save when deeply located. The subcutaneous forms are intimately related with the overlying skin, and have a dough-like consistence which is usually pathognomonic. Tumors, suspected to be fatty, in the middle line of the back or cranium are always to be viewed with suspicion, as they are often connected with congenital meningeal protrusions.

An encapsulated lipoma when thoroughly removed will not return.

Mixed forms of fibrous and fatty neoplasm are occasionally seen, and are referred to as _lipoma fibromatosum_ or _fibroma lipomatosum_, according as one or the other tissue predominates. These growths are innocent in their character, but call for thorough extirpation. They frequently give rise to considerable discomfort or pain, and are called _lipoma dolorosa_.

=Fibroma.=--Fibromas are tumors composed of fibrous tissue, which, when of pure type, are found to be not so common as was formerly supposed, the majority of tumors hitherto roughly grouped as fibromas containing either muscle tissue or sarcomatous elements, which takes them out of the category of pure fibroma. A typical fibroma is ordinarily dense, and is composed of wavy bundles of fibrous tissue whose cells are long and slender and closely packed together, the mass being permeated by distinct bloodvessels.

Fibroma occurs most commonly in the _ovary_, the _uterus_, the _intestine_, the _gum_ (epulis), in _nerve sheaths_, and in the _skin_ in the form of so-called _painful subcutaneous tubercles_ and _molluscum fibrosum_. There is also a fibrous tumor of the skin, known as _keloid_, sustaining to fibroma the same relation that exists between exostosis and osteoma.

_Painful subcutaneous tubercle_ is a sample of pure fibroma in the shape of a small, flattened, pea-like tumor which never attains great size. It is situated loosely in the subcutaneous structure and may form a visible prominence. Insignificant as it would thus appear, it becomes the seat of exasperating pain, particularly when touched or handled, which may radiate to considerable distances. The etiology of these growths is unknown.

In the ovary, the uterus, the intestine, and the larynx true fibrous tumors are pathological curiosities rather than common lesions.

[Illustration: FIG. 74

Keloid of external ear: _a_, dense tissue of skin; _b_, fibrous connective tissue; _c_, epidermis. (Klebs.)]

=Epulis.=--Epulis means any tumor growing upon the gum. The term was formerly applied in an indistinct and too comprehensive way, although it is still retained in literature. But pure fibromas do spring from the fibroösseous structure of the gum and alveolar process. They are covered with the gingival mucous membrane and seem to spring from the periodontal membrane. They seldom attain large size, and then only by neglect. By the pressure of such tumors teeth may be separated and distortion of the mouth produced. They should be promptly extirpated.

=Keloid.=--Keloid is a fibrous neoplasm arising mainly in cicatricial tissue, which is essentially fibroid in structure. It is a neoplasm which often follows the general outline of the scar in which it grows, consists in elevation of the surface, ordinarily quite smooth, sometimes of a delicate pink from the dilated vessels which it contains. Keloid is the _bête noir_ of surgeons, as it frequently complicates and disfigures scars which have at first been satisfactory, and since it indicates a condition which it is discouraging to deal with, because when it is removed there is usually recurrence of growth within a few months after cicatrization. It often occurs in stitch-hole scars and upon the site of extensive burns, and may be observed after puncture of the ears for ear-rings, and has also been observed in scars left by smallpox, acne, etc. It is more prevalent in the colored race than in the white. In negroes multiple keloid tumors are often seen, occasionally in large numbers. Their explanation is unknown, and it may be that some trifling injury has preceded each individual tumor (Fig. 74).

The _treatment_ of _keloid_ will be considered in the chapter on the Surgical Diseases of the Skin.

=Desmoids.=--This term has been applied to tumors of a certain clinical type which arise from the fibrous structures, usually of the abdominal wall, and produce neoplasms like the fibromas of other parts of the body. The use of the term should be restricted to those tumors which proceed primarily only from muscles, tendons, and aponeuroses, or perhaps from ligamentous and periosteal tissues. These tumors are usually single, attain sometimes considerable size, grow slowly, rarely involve other structures, and not infrequently develop to such an extent as to encroach upon either pelvis or the abdomen, or both. They have been known to attain to the weight even of ten pounds or more. They are usually more or less encapsulated, and are firm and dense in structure. Under the microscope they have the general appearance of cellular fibroma. Sarcomatous elements may be met, while they occasionally undergo cystic degeneration. Their occurrence may be explained, at least in some instances, on the embryological theory of Cohnheim.

[Illustration: FIG. 75

Multiple enchondromas.]

The _treatment_ of desmoids consists in their complete extirpation. They should not be allowed to attain large size because their removal may entail a serious weakening of the abdominal wall. There should be such plastic rearrangement of abdominal protecting membranes as to reduce the resulting weakening to a minimum.

=Psammoma.=--Psammoma is a term applied to a form of hard fibroma met with in the dura mater, in which there has occurred a petrefaction of some of the cells--_i. e._, a deposition of calcareous salts, which gives it a gritty or sandy appearance.

=Chondroma.=--The true chondroma is a tumor _composed of hyaline cartilage_. It occurs in the long bones, usually in relation with epiphyseal cartilages, and is often noted during the earlier years of life. While it is usually a solitary tumor, multiple chondromas are often seen, especially upon the hands. These tumors are often encapsulated and form deep hollows, in which they rest. Unless pressing upon nerve trunks they are painless and slow of growth. They are exceedingly dense and hard, and ordinarily immovable. _Mucoid softening_ (_i. e._, _cystic degeneration_) is common, and the softened areas may give rise to fluctuation. There may be coincident _calcification_ or _ossification_ in any of these growths. It is noted as a curious circumstance by Sutton that their tissue resembles histologically the bluish, translucent, epiphyseal cartilage seen in progressive rickets.

To the small local hypertrophies of cartilage which are seen especially about joints, about the laryngeal cartilages, and the triangular cartilage of the nose, are given the term _ecchondroses_. They are most common in the knee in connection with rheumatoid arthritis, and occur as prominences along the margins of the joint cartilage. They may project to such an extent as to be detached by accident, after which they become movable and floating bodies in the joints. Many of the floating cartilages or bodies found in joints are detached ecchondroses, which may be smoothed off by attrition, and may be found singly or multiple, even several hundred existing in one joint.

_Chondromatous changes_ as occurring in _sarcomatous tumors_ have been alluded to. It seems to be easy for connective tissue to form hyaline cartilage, and mixed tumors may thus be seen in connection either with sarcoma, fibroma, or other forms.

=Treatment.=--The treatment of chondroma is solely operative. Unless the integrity of a member or a limb be compromised, such a tumor can usually be shelled out from its location, but requires that the matrix be completely extirpated; all of which may call for the use of powerful bone instruments. At other times _amputation_ is the only measure which may relieve from deformity, pain, and disability. The _ecchondroses_ occurring within joints necessitate incision and evacuation, with the most rigid aseptic precautions, with or without drainage. When practised according to modern technique this is almost invariably successful. In former times many lives were lost because of septic infection.

=Osteoma.=--Under the head of nomenclature I have already endeavored to distinguish as between _exostosis_, or irregular bone outgrowth, and _osteoma_, as a distinct tumor which is composed of bone tissue, with the subvariety _odontoma_, or tumors of dental origin and structure. Osteoma is regarded by some as ossifying chondroma, for it is nearly always found near epiphyseal lines, and is always covered by hyaline cartilage when thus found. Nevertheless it is not invariably such. We speak of _compact_ or _ivory_ osteoma and of a _cancellous_ form. The former is identical with the compact tissue of the shafts of long bones, and may occur anywhere, but is most common about the cranium, at the frontal sinus, the external meatus, and the mastoid process. Osteomas growing into the frontal sinus of oxen form large, lobulated, bony masses, sometimes weighing several pounds, and as dense as ivory. Some of these tumors growing into the cranial cavity have been regarded as ossified brains. Osteomas in connection with the external auditory meatus may partially obscure this channel and cause deafness. They constitute _ivory-like growths_, which sometimes defy the finest steel instruments with which the surgeon can supply himself.

[Illustration: FIG. 76

Double osteoma of the skull. (Musée Dupuytren.)]

Cancellous osteomas grow in the cranium as well as in the long bones, and, like the compact forms, only occasion pain by pressure upon nerve trunks.

=Exostoses.=--Exostoses are classed by Sutton as--

1. Those formed by _ossification of tendons_ and their attachments. There should be excluded from this group such natural or evolutionary processes as the supracondyloid process, the third trochanter of the femur, etc. Over or around such exostoses bursæ will form to mitigate as much as possible the effect of friction. Such an outgrowth is known as an _exostosis bursa_; it is most frequently seen on the inside of the femur immediately above the knee.

2. _Subungual exostoses_, occurring usually beneath the nail of the big toe.

3. Exostoses due to _calcification of inflammatory exudations_, including the rare condition known as _myositis ossificans_.

[Illustration: PLATE XVII

FIG. 1

Round-cell Sarcoma. (Low power.)

FIG. 2

Spindle-cell Sarcoma. (Low power.)]

When a true osteoma is once thoroughly removed there is no tendency to recurrence. Thorough removal, however, calls sometimes for serious and often mutilating operations, which may become dangerous when the growth involves the curve of a rib or a large portion of the skull. At other times amputation is rendered necessary. Special forms require special treatment.

=Sarcoma.=--Formerly this name implied a fleshy tumor, and was made to cover many different conditions. Now _sarcoma means a tumor composed of immature mesoblastic or embryonic tissue in which cells predominate over intercellular material_. Sarcomas are sometimes encapsulated; they merge into and infiltrate the surrounding tissue and disseminate widely, and have usually these propensities and characteristics to such a degree as to constitute malignancy. For the laity sarcomas and carcinomas are together included in the comprehensive term of _cancer_; for the surgeon they constitute but one form of cancer. Sarcomas are classified, according to the shape of their cells and their disposition, into--

A. _Round-cell_;

B. _Spindle-cell_;

C. _Myeloid_.

To these are added other varieties mentioned below.

[Illustration: FIG. 77

Osteoma of frontal sinus. (Neisser.)]

[Illustration: FIG. 78

Recurring sarcoma of parotid. (Original.)]

A. =Round-cell Sarcoma.=--This is simple in construction, and consists of round cells containing very little intercellular substance. The nuclei of the tumor cells stain easily, the cells themselves varying in size in different cases. Bloodvessels lead up to the tumor, but in the interior appear rather as channels. These tumors have no lymphatics: they grow rapidly, infiltrate easily, recur quickly, and give rise to numerous metastatic or secondary deposits. They may affect any part of the human body. The size of the cells is supposed to be in some measure an index of their malignancy--the smaller the cell the more malignant the tumor. They appear at all periods of life. They are perhaps the most commonly seen of malignant tumors in animals. (See Plate XVII.)

=Lymphosarcoma.=--This tumor is composed of cells similar to the previous form, but enclosed in a delicate meshwork resembling that of lymph nodes, hence the term _lymphosarcoma_. Lymphosarcomas are not to be confounded with enlargements nor with the specific granulomas involving these lymphatic structures.

B. =Spindle-cell Sarcoma.=--In this form the cells have a spindle shape and run in all directions, so that sections will show them in various shapes and sizes. In some cases the cells are small and slender, in others large. The size of the cell is a measure of the malignancy of the tumor. (See Plate XVII.)

The largest of these spindle cells are frequently striated transversely like voluntary muscle fiber, and tumors composed of this form have been considered as tumors of striped muscle tissue, and are generally called _rhabdomyoma_. There is no tumor of striped muscle fiber, and the rhabdomyomas of writers generally should be considered as spindle-cell sarcoma, or may be dignified by the name _myosarcoma_. (See Rhabdomyoma, under Myoma.)

=Alveolar Sarcoma.=--This is a rare form, in which the cells, contrary to the general rule of sarcomas, assume an alveolar arrangement strongly imitating that of epithelial cells in carcinoma. Almost invariably, however, on close examination it will be possible to distinguish a delicate reticulum between individual cells, which is never met with in cancer.

C. =Myeloid, or Giant-cell Sarcoma.=--In this form the tissue resembles histologically the red marrow of young and growing bone, containing large numbers of multinuclear cells embedded in a matrix of spindle or round cells. These tumors usually occur in the long bones, and when freshly cut look like a piece of liver. They constitute most of the _epulides_ or cases of _epulis_--_i. e._, spongy tumors springing from the gums. (See Plate XVIII., Fig. 2.)

[Illustration: FIG. 79

Sarcoma of femur following fracture--_i. e._, developing in callus. (Original.)]

Giant or multinuclear cells should be present in considerable numbers to entitle a tumor to classification in this group. When round cells, spindle cells, or giant cells mingle in nearly equal proportion the tumor should be called a _mixed-cell sarcoma_.

D. =Osteosarcoma.=--Osteosarcoma is something more than sarcoma of bone, which latter may spring from the fibrous or medullary elements. It is sarcoma of the specific bone-forming connective tissue, including the osteoblasts and osteoclasts; in other words, of the stroma of the bone. Under these circumstances real bone develops throughout the tumor, and it is essentially a bony neoplasm. In like manner there may be true _osteofibroma_. These tumors are to be distinguished, even clinically, from the medullary sarcomas, which develop within the bone and expand it, even to enormous proportions, the bony covering then being a mere shell.

E. =Chondrosarcoma.=--Chondrosarcoma resembles osteosarcoma in that it is sarcoma of the stroma of cartilage, or of the specific tissue which produces cartilage. In it true cartilage (white fibrous) also is found throughout the tumor. Chondrofibroma is also possible. (See Plate XIX.)

F. =Endothelioma.=--Endothelioma has been called various names, and its true character has been only lately determined. It is composed

## particularly of the endothelial cells which line the lymph spaces, and

which have no peculiar secretion. It is met with most often in the skin (especially of the face), in the parotid region, in the genital glands, the bones, the lymph nodes, and dura.

[Illustration: PLATE XVIII

FIG. 1

Angiosarcoma. (Low power.)

FIG. 2

Giant-cell Sarcoma. (High power.)]

[Illustration: PLATE XIX

FIG. 1

Chondrosarcoma. (Low power.)

FIG. 2

Osteosarcoma. (Low power.)]

[Illustration: PLATE XX

Melanosarcoma of Skin. (Dry high power.)]

The microscopic picture of these tumors varies greatly, the endothelial cells often shaping and grouping themselves so as to imitate epithelioma. In doubtful cases the primary location or origin of the growth should be ascertained.

Endotheliomas are mainly of rapid growth, and often show a high degree of malignancy. If thoroughly extirpated before metastasis has occurred, prognosis is fair; but metastases happen early because of the direct connection of the tumor with the lymph current.

[Illustration: FIG. 80

Endothelioma of the soft palate: _a_, dilated lymph space; _b_, endothelial cells with beginning cystic formation; _c_, completely formed cyst. (Volkmann.)]

G. =Angiosarcoma.=--Angiosarcoma is a sarcoma arising from the adventitia of the bloodvessels. It is characterized by its extraordinary vascularity, the ease with which hemorrhages into the structure of the tumor take place, and the frequency of pigmentation. _Peritheliomas_ constitute a subvariety, met with especially in the kidneys, the bones, and the skin, and originate in the perithelial cells between the capillaries and the perivascular lymph spaces. They are more vascular than the angiosarcomas. The latter are common in the liver. In many cases the cells of these tumors simulate the columnar epithelium of adenocarcinoma. (See Plate XVIII, Fig. 1.)

H. =Cylindroma.=--This is a term applied to tumors of the angiosarcomatous type in which hyaline changes have occurred, so that along the vessels appear cylindrical masses of altered cells. Similar appearances are noted in certain endotheliomas and are due to the same hyaline degeneration.

I. =Melanosarcoma= (_better known as Melanoma_).--This refers to the deposition of pigment, rather than to type or shape of cell, the distinguishing feature of these growths being the presence both in the cells and in the intercellular substance of a variable quantity of blackish pigment. Of all the forms the melanotic growths are considered the most malignant. They invariably recur after removal, lead to secondary deposits at long distances, and present the most intractable and incurable forms of cancer. Deposition of pigment in carcinomas is most rare, if ever met with, and the growths of melanotic type should be relegated entirely to the class under consideration. The tumors most often develop from pigmented nevi of the skin, though primary melanoma of the deeper parts of the body is known. These will be treated more fully in the chapter on the Skin. (See Plate XX.)

This name has been variously applied by different writers to different growths. In order to avoid confusion it would be well, in using it, to be definite.

=General Characteristics of Sarcomas and Endotheliomas.=--The vascular supply of sarcomas varies within wide limits. In nearly all instances it is of capillary character, the blood circulating rather through vessels without well-marked walls. While large vessels may be found about and in the periphery of these tumors, distinct vascular structure is usually absent from the more internal portions, which will explain the frequency of hemorrhage, its persistency after operation, and the ease with which large extravasations occur. True hematocele may thus take place within sarcomatous tumors, with the usual later cystic alterations, and thus in one way we have the condition known as _cystosarcoma_.

In attacking these growths the vascular and bloody area may be met just about their margins, the bloodvessels expanding as they arrive at the tumor, and sometimes bleeding extensively. Under most circumstances, however, this hemorrhage can be controlled by packing or by operating at a greater distance from the circumference of the growth.

_Metastasis in sarcoma is common_, dissemination occurring mainly along the veins, as these growths connect with the venous channels and permit of easy detachment of fragments, which are then carried along as emboli. These emboli pass naturally to the right side of the heart, and thence to the lungs, where it is most common to find secondary growths, except in areas emptying into the portal veins, in which case the liver will be the most common site. Sarcomas are destitute of lymphatics, and dissemination does not occur through these channels.

Infiltration is also a common phenomenon with these growths. This is generally seen in muscular tissue, particularly with growths proceeding from the periosteum and projecting into it.

Sarcomas, like other tumors, tend to grow along the lines of least resistance. Hence processes of these tumors will insinuate themselves into fissures and interspaces, and penetrate perhaps even into the cavities, from which it is hazardous or impossible to remove them. Thus, sarcomas springing from the head of a rib have been known to extend through an intervertebral foramen and give rise to an intraspinal tumor, causing fatal pressure.

_Secondary changes_ are usually seen in sarcomas, the most frequent being hemorrhage. _Myxomatous degeneration_ is also frequent, and gives rise to _cystic_ conditions. _Calcification_ is common, particularly in the slowly growing tumors which arise from bone. Upon the other hand, _necrosis_ (_i. e._, ulceration) is common in growths which project upon the surface or into any of the open cavities of the body. Ulceration here is growth at a rate faster than nutrition will justify, and gangrene is to be regarded as a failure to supply sufficient blood. It may also mean infection, of which it is a usual expression.

Tumors of this character, which luxuriate upon reaching the surface, and bleed easily upon the slightest touch, were formerly known as _fungus hematodes_. The name may be preserved for the sake of convenience, but should be held to mean, in almost every instance, a rapidly growing round-cell sarcoma.

Sarcoma is common in the lower animals, particularly so in horses--most common in those of gray color. It is met with also in cows and various other domestic and undomesticated animals.

=Myxoma.=--The myxomas are composed of _mucous tissue_, whose best-known normal representative is the Whartonian jelly of the umbilical cord. True myxoma should be distinguished from _myxomatous degeneration_, which occurs frequently in cartilage, fibrous tissue, and sarcoma, and which brings about a similar condition of affairs, though of essentially different origin. Myxomas appear under the following forms:

1. =Polypi.=--These include many of those which grow in the nose. The pure form of nasal myoma proceeds from the mucous membrane of the nasal passages or sometimes from the accessory sinuses. But most of the so-called nasal polypi are due to edematous hypertrophies of the submucosa. The polypi usually hang as gelatinous tumors of grayish-yellow tint, being present sometimes singly, sometimes in clusters or in large numbers. Their principal effect is to produce nasal obstruction, with, perhaps, subsequent serious disorder, due to decomposition or to extension into the pharynx or other cavities. Similar growths also occur from the mucous membrane of the tympanum, and constitute the common variety of aural polypi.

2. =Cutaneous Myxoma.=--Cutaneous myoma is not common. It presents usually as a sessile tumor, although about the perineum and labia the tumors may become pedunculated. It is often difficult to distinguish between a myoma of the skin and a sarcoma of the same which has undergone myxomatous degeneration, and which then should be called sarcoma myxomatodes. The latter tend to recur after removal; hence the importance of exact diagnosis.

3. =Neuromyxoma.= Neuromyxoma is a similar condition involving the nerve trunks, and is dealt with under Neuroma.

Myxomas require complete removal, and, in the nose especially, cauterization or destruction of the surface from which they spring. When this is thoroughly done they do not recur; otherwise, they are likely to require subsequent operation.

=Myoma.=--The true myoma is a tumor composed of _unstriped_ or _involuntary_ muscle fiber. Until recently it has been customary to divide the myomas into the _leiomyomas_ in contradistinction to the _rhabdomyomas_, the latter being supposed to be tumors of voluntary muscle fiber. _Myomas_ are met with only where _involuntary muscle fiber_ is found--namely, in the uterus and adnexa, the vagina, the esophagus, alimentary canal, the prostate, the bladder, and the skin. They form _encapsulated_ tumors composed of fusiform muscle cells with a rod-like nucleus, the size of the cells varying greatly in different specimens. The bundles of muscle fibers are much contorted, and it is often difficult in a single section to decide to just what class of cells they belong.

These tumors are most common in and about the uterus, and are referred to as _intramural_ when developing in the true uterine tissue, and _submucous_ and _subserous_ when situated just beneath one or the other of the adjoining membranes. They differ in their rate of growth, are firm in composition, and are moderately vascular, sometimes containing areas of softening and becoming even cystic. In rare instances they become enormously vascular, and are then known as _cavernous myomas_. Aside from mucoid or colloid changes they occasionally undergo fatty metamorphosis or calcareous infiltration. The latter is possible to such an extent as to lead to a condition of _uterine calculi_.

Uterine myoma is liable to septic infection, which frequently follows exploration of the uterus or the changes incident to pregnancy or parturition. It then becomes a case for immediate operation. Uterine myomas do not occur before puberty, rarely before the age of thirty-five, and are most common between the thirty-fifth and forty-fifth years of life. They produce disaster not alone by their size, but by hemorrhage, by pressure on adjoining viscera (rectum, kidneys, etc.), and occasionally by torsion of a long pedicle.

Myomas are found in the _esophagus_, in the walls of the _stomach_, where they are frequently confounded with malignant tumors, in the _prostate_ and wall of the _bladder_, and in connection with the _skin_. As soon as they give rise to inconvenience or to dangerous symptoms they are to be dealt with surgically, as no other treatment has proved of lasting benefit.

The _rhabdomyomas_ deserve but brief description. The striated muscle fibers of which these tumors are composed have been often confused with spindle-shaped sarcoma cells. They are met with almost exclusively in the mixed tumors of the kidney under Teratomas.

Myoma or myofibroma is exceedingly likely to undergo sudden conversion into a form of growth entitling it to be called _malignant myoma_.

=Angioma.=--Angiomas are tumors composed of bloodvessels, and group themselves under three headings, in accordance with the structure of the vascular system:

1. =Capillary Angioma, or Nevus.=--Capillary angioma, or nevus, is the most common form of all, and is frequently seen in the skin and subcutaneous tissue. When the condition is spread over a relatively large area it gives rise to a discoloration known as _port-wine mark_, and called _telangiectasis_ by the pathologists. The condition is often congenital or begins soon after birth. The color of the affected area determines whether the vessels belong to the venous or to the arterial system. These tumors may be found in all parts of the body, on the surface, on the submucous surfaces of the tongue, the inside of the mouth, the conjunctiva, and the vulva. The tendency is toward gradual increase in size; rarely, spontaneous contraction and obliteration occur.

2. =Cavernous Tumors.=--These are similar in structure to the corpus cavernosum, and are called _erectile tumors_. They are common in connection with the skin, and are exaggerated forms of the variety first described, the vessels becoming not merely dilated but cavernous in arrangement. They occur occasionally in the tongue, in the voluntary muscles, and in the liver, and are noted very rarely in the mammæ, in the larynx, and subperitoneally.

A similar condition is met with in the so-called cavernous tumors which involve various organs, especially the thyroid and the liver. In these instances a part or the whole of the organ may be involved, and presents great increase in size and evidences of vascularity.

In cavernous growths of the thyroid are vessels, veins especially, the size of the thumb, while with the ear not touching the body of the patient a distinct venous murmur may be heard.

3. =Arterial or Plexiform Angiomas.=--Arterial or plexiform angiomas, when of any particular size, are called _cirsoid aneurysm_ or _aneurysm by anastomosis_. This form consists of arteries abnormal both in number, length, and diameter, tortuous in arrangement, occurring often in the scalp, but rarely in the perineum or genitalia, and seldom in other parts of the body. (See Aneurysm,