CHAPTER XXVI
.
CYSTS AND TUMORS.
GENERAL CONSIDERATIONS.
A tumor _is a new formation, not of inflammatory origin, characterized by more or less histological conformity to the tissue in which it has originated, and having no physiological function_.
By the above definition it is intended to separate the new-growths from a distinctive class of neoplasms which are of inflammatory (_i. e._, of infectious) origin, to which the generic term of _infectious granulomas_ has been given. (See Part II.)
Exceedingly vague notions have prevailed concerning the _nature_ and _origin_ of tumors, and, while the clinical observations of writers in the past will never lose their value, the ideas which have prevailed concerning their pathology constitute interesting reading in a historical sense, but are now of small value. Accurate notions scarcely prevailed until Virchow demonstrated that tumor cells nowise differ from cell types which are met either in embryonic or in adult tissues. Tumors, like all other parts of the body, are built up of cells, and the points concerning which we need most light regard the influences which determine cell overproduction in these characteristic forms. Concerning the views that have prevailed, this is scarcely the place in which to offer an epitome. I shall therefore take up but few of the explanations which have been offered to account for tumor growth, and will emphasize that, according to our present light, there is no explanation sufficient to cover all cases, but that it is now one cause and now another which may determine this peculiar form of cell activity.
=Irritation and Trauma.=--The effort is often made to explain the presence of tumors upon the hypothesis or the known fact of some previous injury. Frequently tumors appear in sites where there have been previous traumatisms, but this sequence of events by no means proves a definite relation of cause and effect. On the other hand, there are forms of irritation which are often followed by tumor formations. Probably no woman escapes without one or more bumps or bruises upon the breast, yet they do not produce tumors in more than a trifling proportion of cases. _Per contra_, upon the lower lip of inveterate clay-pipe smokers and the scrotum of chimney-sweepers there develop certain forms of malignant ulcer (epithelioma) which so often and so significantly follow upon the irritation thus produced that it is impossible to avoid conviction that one is the cause of the other. Should events prove the parasitic nature of any of these growths they will also prove that the irritation causes surface lesions through which infection easily occurs. In regard to the relative frequency with which cancer in some form follows trauma we should not forget the well-known fact that traumatism usually diminishes tissue resistance. If cancer be an expression of infection, as many (including the writer) believe, the possible relation between trauma and malignant disease may be better appreciated.
=Inflammation.=--This refers to inflammation in the sense in which it has been used in the past, implying a variable condition, sometimes including and sometimes excluding infection, the term covering a confused mixture of irritation, hyperemia, and infection. In so far as it concerns inflammation as considered in the present work it should not be here included, since inflammation (_i. e._, infection) produces neoplasms of a class considered in Part II and is distinctly ruled out from present consideration (_i. e._, the infectious granulomas).
If inflammation in the former sense be more than hyperemia it may be regarded as predisposing to cell activity, but not necessarily to tumor formation as distinguished from hypertrophy of a given part or tissue. If it refer to irritation, this has been acknowledged as a factor in the etiology of tumors, but as an uncertain one. Cancer of the gall-bladder or liver, which occasionally results from the irritation of a gallstone, or the cancer of the breast that follows eczema of the nipple, may be regarded in this light as additional illustrations if it is preferred to interpret them in this way. If by inflammation be meant the infectious granulomas, they have already been considered. As the term “inflammation” can scarcely mean anything except hyperemia, irritation, or infection, we seem to have completely ruled it out from consideration as by itself an active cause leading to tumor formation.
=The Embryonal Hypothesis of Cohnheim.=--This in its ingenuity and in its applicability is a fascinating explanation, which is undoubtedly sufficient for at least a certain number of instances. According to Cohnheim, only one causal factor for tumors exists--_i. e._, _anomalous embryonic arrangement_. He regards them as _entirely of embryonal origin_, no matter how late in life they may develop and appear. Briefly summarizing his views, they are to the effect that in the early stages of embryonal development there are produced more cells than are necessary for the construction of a certain part, so that a number of them remain superfluous. While these may remain very small, they possess, on account of their embryonal nature, a potent proliferating power. This superfluous cell material may be distributed uniformly, in which case it will develop whole system arrangements, like supernumerary fingers, etc., or it may remain by itself in one place, and will then develop a tumor. In the latter case the tumor may appear early or not until late in life, according to the time at which the cell collection receives the necessary stimulus, or because of its suppression by resistance of surrounding structures. It may be an irritation or an injury, such as above alluded to, which shall give it this stimulus; as, for example, it is reasonable to think that certain nevi and other congenital conditions which develop later into cancers do so in accordance with this view. Surgeons generally find little fault with Cohnheim’s hypothesis, except that as yet they decline to see in it an explanation for all cases. Nevertheless for dermoid and teratomatous, and for all heteroblastic tumors, it seems to afford the only tenable explanation. Thus chondromas of the parotid and of the testicle are most easily explained in this way, and that cartilaginous islands occur in the shafts of adult bones is well known.
=Heredity.=--In regard to heredity being a factor in the etiology of neoplasms there is reason to believe that a favorable tissue disposition may be inherited, but there is nothing to show that it permits the actual transmission of the disease.
=Parasitic Theory.=--The _parasitic theory of tumor formation_ has only within a few years taken definite form and shape, as a result of evolution from vague suggestions and scattered observations. It implies that tumors, and they are mainly of the malignant type, are due to irritation produced by extrinsic agencies, _parasites of some kind_, which, introduced from without, act as do bacteria in the now well-known infectious granulomas. While this theory, perhaps, does not afford an absolutely satisfactory explanation of all the phenomena of malignancy, it nevertheless comes nearer to it than does any other hypothesis now before the profession, the arguments in favor of it being scientific and positive, and those against consisting mainly of mere negations. Summed up these arguments may be stated as follows:
1. =Comparative Pathology.=--The argument from _comparative pathology_ begins with the lower forms of life. Tumors in trees and plants are well known to vegetable pathologists and botanists as of frequent occurrence. They vary in size from the most trifling galls to those large woody masses known as xylomas, which are essentially tree cancers, since they tend to the destruction of the tree. These are known to be invariably due to extrinsic agencies, such as insects, fungi, etc. As water freezing in the bark of a tree may crack it open and thus leave opportunity for subsequent infection, so may injuries upon the body surface make trifling lesions which predispose to subsequent infection and cancer in man and animals. Exclude parasites from such traumatic lesions on plants and there will be no xylomas.
[Illustration: PLATE XIV
Adenocarcinoma with Young Parasites. (Parasites blue. Plimmer’s method.)
This plate is introduced to illustrate the _presence_ of parasites, whose minute and actual character is not yet positively determined, but whose existence is undeniable.
From Gaylord’s paper in the Third Annual Report of the New York State Pathological Laboratory of the University of Buffalo.]
[Illustration: PLATE XV
Rapidly Growing Carcinoma of Breast.
The parasites herein demonstrated are still subjects of careful and minute study. It would therefore seem premature to make detailed statements concerning their exact nature.
From Gaylord’s paper in the Third Annual Report of the New York State Pathological Laboratory of the University of Buffalo.]
[Illustration: PLATE XVI
FIG. 1. Parasites, at one time called Russell’s Bodies, at Periphery of Epithelioma of Tonsil. (Oil immersion.)
FIG. 2. Same in Lymph Node before Epithelial Invasion. (From N. Y. State Path. Lab. Rep.)
FIG. 3. Papillary Adenocarcinoma of Ovary, showing Intracellular Ameboid Forms of Parasites. (From N. Y. State Path. Lab. Rep.)]
2. =The Analogy Afforded by the Infectious Granulomas.=--These are universally conceded to be of parasitic origin, while their clinical course and behavior in every respect make many of them almost as malignant as the true cancers become.
3. =Metastasis.=--This is in every other disease considered to be one of the most significant expressions of infection, yet until recently few of those who have willingly accorded to metastasis its now common interpretation in tuberculosis have been willing to give it the same dignity as a factor in the spread of cancer and an important explanation of its nature. Why should every other disease characterized by metastasis be everywhere viewed as parasitic, and cancer, in which occur some of its most positive expressions, be denied? _Metastasis has the force and significance of an inoculation experiment performed under favorable circumstances._
4. =Evidence of Local Infectivity.=--The involvement of a part which has lain in contact with a cancerous lesion, as about the mouth or the vulva, and in many other ways and places of which medical literature is now full, and the instances of cancer following the knife wound, especially following the track of the trocar used for tapping a case of cancerous ascites, stamp the disease as having an infectivity which cannot be explained on any inherent property of its own.
5. =Microscopic Appearances.=--While it is true that but few observers have been able to agree upon a definite cancer parasite, it is also true that many of the best observers have seen, described, and figured bodies that do not belong in the cells of a cancerous growth except they are there in the roll of active agents, and the appearances which have been described by Pfeiffer, Plimmer, Gaylord, Calkins, and others are not to be explained away as mere artefacts, but must be given a place in our estimation which they would attain of themselves, as exciting suspicion, were there no other facts corroborating the views that they are in some way actively connected with the production of the disease. (See Plates XIV, XV, XVI.)
6. =Inoculation Experiments.=--No feasible plan has been devised for practising inoculation experiments upon human beings. It is known, however, that the disease may be transmitted in some cases among animals of the same species, and the transfer has been made in a few instances from man to the lower animals. In the Gratwick Laboratory (Buffalo) the disease has been thus transmitted through hundreds of mice, and has thus afforded the best means of studying it in its varied phases, albeit in small animals, ever yet enjoyed. But cancer does occur in animals and has proved to be capable of inoculation, and, therefore, has responded to one of the severest tests of the value of the theory. Moreover the facts cited above (under 4) are essentially successful auto-inoculation.
7. =Clinical Observations.=--Add to the features already mentioned above those impressions which come from accurate observation and correlation of the phenomena attending many cases of cancer, and a plausibility is thus lent to the parasitic theory which it can never gain from study in the dead-house or through the microscope. The resemblance between it and other known infections, the local and general alterations of tissues and fluids, the chemical changes by which the cachexia of the disease is brought about--these with other features all conspire to give the keen observer of cases of cancer an impression of parasitism or infectiousness which nothing can efface. Add to these its endemic, sometimes almost epidemic occurrence, its apparent transmission by contact, and the fact that it is but little influenced either by nutrition or drugs, and the argument is still strengthened. As against these arguments little has been advanced save denials or negations.
In thus upholding the parasitic theory, the writer would not wish to be understood as claiming either that the parasite has yet been discovered or its nature positively made out, nor that it is a question of one organism alone; rather, on the contrary, he feels that it is probably a question of several agents, probably of protozoan character, perhaps too small to be recognized with the lenses of today, perhaps belonging to some as yet unstudied class of organisms, making themselves known, however, as do the hypothetical parasites of syphilis and scarlatina, by their effects. To accept the parasitic view is to reconcile many discrepancies of earlier times and to give an entity to the disease by which, and until something better be found, we may be more safely guided in its management.
The parasitic theory lends plausibility to the statement which the writer wishes to emphasize, that cancer, like many of the other infectious diseases, is at first a local condition, that it is not transmitted by inheritance, and that there is a time in the history of every cancer when, _if_ it could be recognized sufficiently early, and _if_ it were also accessible and thoroughly removed, _it could be cured_.
=Nomenclature.=--The nomenclature of tumors has been much confused, and if some new terms are introduced it is perhaps better than to cling to some which have prevailed in the past. Various systems have been followed of naming them according to their supposed nature or their evident tendency, or according to some purely arbitrary classification; thus there is the distinction into _homologous_ and _heterologous_ or _heteroplastic_, according as they are similar to or variant from that tissue in which they seem to originate; or they have been referred to as _benign_ and _malignant_ according to the disposition which they evince; and these terms are in sufficiently frequent use to demand acceptance. The distinction between benign and malignant is convenient and in some respects accurate, implying little in regard to histological structure, but much in regard to their effect upon the individual.
So far as _method of classification_ goes, the _anatomical_ (_i. e._, the _histological_) has proved far the most satisfactory, and is that which is now generally adopted. It is the basis for the classification followed in the ensuing pages. But even here it is impossible to maintain abrupt or always accurate distinctions, because tumors are frequently of mixed type, and it is required, if desired to express their composition by their names, to sometimes combine words in an awkward fashion.
By common consent that tissue which predominates furnishes the concluding portion of the compound term, while by prefixing other terms we endeavor to imply the composite character of the neoplasm.
Thus we have _osteochondroma_, _fibromyoma_, _myofibroma_, etc., and it is necessary often to reduplicate terms in order to be accurate in description. While this complicates phraseology, it nevertheless furnishes to the reader a reliable clue as to the general character of such a growth; and if one reads, for instance, of a _myxochondrosarcoma_, he promptly infers therefrom that thereby is meant a tumor essentially a sarcoma, in which both myxomatous degeneration and cartilaginous formation have taken place.
In the same way the prefix _cysto_ is frequently used to imply a combination of originally solid tumor which had undergone cystic changes in whole or in part.
The old term _cele_ is frequently used as a suffix, implying neoplastic changes in an organ, or at least the formation there of a tumor. Thus we have _bronchocele_, _hydrocele_, and _cystocele_. Again, certain terms are used in a different sense from that originally intended. Thus the term _sarcoma_ has a definite significance, whereas originally it had little meaning and was applied inadequately and indiscriminately. Old terms also, like _fungus hematodes_, are now used rather in a descriptive sense, because for any such tumor we can find, on accurate examination, a proper term taken from descriptive pathology. Therefore the student of today should read the works of the older writers, especially concerning neoplasms, with a certain amount of intelligence, as well as of apology for the inaccuracy and misnomers of the past.
TREATMENT OF TUMORS.
The results of treatment of tumors leave much still to be desired,
## particularly when dealing with those of malignant nature. So far as
purely internal treatment is concerned, we have not yet discovered drugs which with any certainty influence cell growth to the extent of making them reliable or effective. In the past, and even at present, numerous remedies have been advocated as having more or less power in this direction. Of them all it is probable that arsenic in some form is more efficacious than any other. This is true in the case of the disease elsewhere spoken of as _malignant lymphoma_, or _Hodgkin’s disease_, which partakes much of the character of some of the other neoplasms. But to say that arsenic alone or any other known remedy can be relied upon at all times is making a bold assertion.
=Operable Tumors.=--The _treatment of operable tumors_ is _essentially surgical_ (_i. e._, _operative_), although to a large extent results are based upon the essential character of individual cases. But it can be stated that to be successful in the removal of any tumor its complete extirpation is imperative. Even the most benign growths will return if only partially removed. This is true even of innocent cysts, which will be often reformed if a portion of the cyst wall be allowed to remain. Complete extirpation is ordinarily a simple measure when tumors are _encapsulated_, as are often many of the innocent tumors. On the other hand, the performance of some of these operations is made difficult and hazardous by the location of the tumor, as in many large uterine fibroids, tumors of the thyroid, etc. But when dealing with malignant tumors the secret of success is to extirpate them, sacrificing everything which may appear to be involved unless, like a large bloodvessel or important organ, it be essential to the life of the part or of the individual. These statements are made when speaking of tumors in a general way. More specific directions will be given when dealing with particular forms or in the chapters on Special and Regional Surgery.
CLASSIFICATION OF TUMORS.
Following custom in large degree, yet being guided by undeniable facts concerning histological structure, tumors will be classified and considered as follows:
1. Cysts.
2. Dermoids.
3. Teratomas.
4. Tumors of connective-tissue type.
5. Tumors of nerve elements.
6. Tumors derived from epithelium.
1. =Cysts.=
A cyst may be defined as a _tumor containing one or more cavities filled with fluid or semifluid contents_. This specifies nothing with regard to the location nor the character of the cyst wall nor the nature of the fluid contents. Following Sutton, I divide cysts into four groups:
_Retention cysts._
_Tubulo cysts._
_Hydroceles, or distention cysts._
_Gland cysts._
=Retention Cysts.=--These imply a previously existing cavity whose outlet is obstructed and whose contents consequently accumulate, often to such a degree that the original character of both containing wall and contained fluid is entirely altered. When this occurs in glands or gland ducts there is usually complete atrophy of gland tissue, providing sufficient time have elapsed. Such cysts are due either to permanent or temporary arrest of flow. In _hydronephrosis_, for example, there is obstruction of the renal outlet and dilatation of its pelvis, with partial or complete atrophy of the kidney structure, until a cyst of enormous size may be present. When a similar condition obtains in the uterus, as by obstruction of the cervix, perhaps due to injury done during labor, we have a condition known as _hydrometra_, seen occasionally in women, often in the lower animals, and
## particularly in those having a bicornate uterus, causing a condition
often mistaken for an enormously dilated Fallopian tube. Similarly, when the common bile-duct is obstructed, which may be due to impacted gallstones, to inflammatory lesions or tumors, there may be such backing up of bile in the gall-bladder as to produce the condition known as _hydrocholecyst_.
Under any of these circumstances pyogenic bacteria may produce infection which will be more or less promptly followed by suppuration; and then, instead of _hydronephrosis, ydrometra_, _hydrosalpinx_, _etc._, we have _pyonephrosis_, _pyometra_, and _pyosalpinx_.
=Tubulo Cysts.=--These are _cystic dilatations of certain functionless ducts and obsolete canals_ which no longer serve a useful purpose. They comprise:
1. =Cysts of the Vitello-intestinal Duct.=--Cysts originating from this functionless duct occupy the umbilical region, sometimes projecting externally, sometimes internally. They are usually lined with mucous membrane furnished with villi and columnar epithelium. Such a cyst may be confounded with an umbilical hernia. These cysts occasionally open at the umbilicus and discharge irritating material, sometimes fecal matter. Cystic dilatation of the portion of the duct originally connected with the ileum is also sometimes seen.
2. =Allantoic Cysts.=--These are connected with the urachus, which should ordinarily be found as a fibrous cord, but which occasionally persists in a pervious condition, in whole or in part. At birth it is often traversed by a narrow canal lined with epithelium continuous with that of the bladder. The urachus lies outside the peritoneum, and may be dilated at any point between its two extremities. When the entire urachus is pervious urine is discharged from the navel.
3. =Cysts Connected with Remains of the Wolffian Body.=--The Wolffian body, or the mesonephros, is intimately related with the development of the kidney, the ovary, and the testis. In the two latter locations glandular elements may be met, persisting in adult life.
In the male the _tubules_ persist as _excretory ducts from the testis_, but in the _female_ they persist, in a vestigial condition, as the _parovarium_ and _Gärtner’s ducts_. The ovary proper consists of the _oöphoron_ and the _paroöphoron_, the former being the egg-bearing portion, the latter receiving the tubules from the adjoining structure known as the parovarium. The _paroöphoron_ gives rise to cysts which burrow deeply between the layers of the broad ligament, make their way alongside the uterus, and raise the peritoneum. It is a peculiarity of these cysts that their inner walls often become _papillomatous_, and may even develop such a crop of warty outgrowths that these make their way through the cyst wall and protrude into the abdominal cavity, where they sometimes become detached and are dropped as loose bodies into the peritoneal sac. The condition is also often accompanied by warty growths upon the peritoneal surfaces. These need give rise to no alarm, because they usually disappear spontaneously with removal of the tumor. _Paroöphoritic cysts_ are to be distinguished from _parovarian cysts_, which develop from the parovarium, this latter consisting of a number of tubules situated between the layers of the mesosalpinx, composed of an outer series known as _Kobelt’s_, an inner set, about a dozen in number, known as the _vertical_ tubules, with a straight tube, running at right angles to these through the broad ligament to the vagina, known as _Gärtner’s_ duct, which is homologous with the vas deferens in the male. Cystic dilatation of Kobelt’s tubes is often seen, these cysts being very small and having no clinical importance. Cysts arising from the vertical tubules are usually transparent until they attain considerable size, when their walls thicken. Their contained fluid is not harmful, and after rupture of such cysts internally the fluid is absorbed. Such cysts may rupture and refill several times. _As between the paroöphorous_ and _parovarian cysts_ the latter are easily enucleated, carry the ovary upon one side, and have the Fallopian tube stretched over them without communication.
The internal sections of _Gärtner’s duct_ are more often involved in animals than in women, but excellent illustrations of cystic dilatation of its various portions have been observed, usually in the walls of the vagina.
Corresponding to the above-mentioned conditions in the female there are in the male, as the result of changes in the Wolffian body, two conditions--_encysted hydrocele of the testicle_, and _general cystic degeneration_ of the same. Like the ovary, the testicle is a complex organ with remnants of the mesonephros persisting among its ducts, while only a few of the Wolffian tubules remain. True encysted hydroceles arise sometimes in the efferent tubes of the testis and sometimes in Kobelt’s tubes (the same structures which in the female give rise to parovarian cysts), the two conditions, therefore, being analogous and homologous. These cysts, though closely associated with the testis, lie outside its tunica vaginalis. Their contained fluid is usually clear or of a milky whiteness, due to fat globules. Sometimes it contains spermatozoa. Another variety is cystic dilatation of one or more of _Kobelt’s tubules_, which is often described as involving the _hydatid of Morgagni_.
_General cystic disease of the testis_, known also as adenomatous degeneration, was formerly referred to as hydatid disease of the same organ. The multiple cysts appear to originate in the remnant of the mesonephros still persisting, known as the _paradidymis_. The cavities are lined with epithelium, and _papillomatous intracystic_ formation is not uncommon. These tumors have been called by a number of improper names, such as “cystic sarcoma,” etc.
=Hydroceles.=--The term hydrocele has covered numerous conditions. At present, when no other locality is designated, hydrocele of the tunica vaginalis is understood. (The term implies a _collection of watery fluid in a previously existing serous cavity_.) This is the most common form.
Possibility of its formation depends upon the prolongation of the peritoneal cavity which takes place in advance of or along with the descending testicle, and which in many of the lower animals remains connected with the general cavity throughout life. In men only is it expected to close, even before birth. When the portion which extends along the spermatic cord is not completely obliterated there is _encysted hydrocele of the cord_, or _funicular hydrocele_, which is not common. The common form of hydrocele is constituted by serous effusion into the tunica vaginalis, and occurs usually without recognizable exciting cause. It will be treated more fully in its appropriate place.
The corresponding process of peritoneum in the female is known as the _canal of Nuck_; and, when persistent, this also becomes distended with fluid and forms a cyst known as _hydrocele of the canal of Nuck_, occupying the inguinal canal.
In many of the lower animals the ovaries are contained within a serous sac derived from the peritoneum, which is so connected with the opening of the Fallopian tubes that when the ova escape from the ovary they enter these tubes and pass to the uterus without entering the general peritoneal cavity. This ovarian sac is subject to serous distention, and constitutes a condition called by Sutton an _ovarian hydrocele_. An homologous condition occurs sometimes in the human female, by pathological adhesion, and such cysts may attain large size. They project from, and are intimately connected with, the posterior layer of the broad ligament.
=Hydroceles of the Neck.=--Hydroceles of the neck, so called, are cystic collections of congenital origin found in the cervical region, due to dilatation of ducts or clefts which should have disappeared at or before birth. The forms of cyst to which the name “hydrocele of the neck” are usually limited are recognizable at or soon after birth, and constitute fluctuating tumors, often extending beneath the clavicle into the axilla or down upon the thorax. They may occupy the entire lateral region of the neck, and may be unilateral or bilateral--may be single or multilocular, and may even intercommunicate.
They originate always beneath the deep fascia. Some of these cysts are undoubtedly due to dilatation of lymph spaces. This is particularly true of the multilocular forms. There is noted in many of them a tendency toward spontaneous recovery, but many again require operative measures for their eradication. Occasionally their walls are extremely vascular, even to the degree meriting the term _nevoid_.
Some of these cysts are considered by Sutton to be essentially examples of the laryngeal saccules which are met with as diverticula from the laryngeal mucous membrane, which undermine the deep cervical fasciæ of certain monkeys. These air chambers, which are normal in the monkey, communicate with the larynx through the thyrohyoid membrane, and occasionally run down beneath the upper border of the thorax. Many of the cysts having this resemblance are closely related to the hyoid bone and to the larynx, and there is much to substantiate the view thus quoted.
=Glandular Cysts.=--_Ranula_ is an altogether too comprehensive term which has long been used in surgery, alluding to cysts in the floor of the mouth, and not indicating minutely their character nor their exact location. At present this term should either be restricted in signification or be eliminated. If used, it should be confined to retention cysts due to obstruction of the _submaxillary_ or _sublingual_ ducts. Such obstruction is often caused by salivary calculi impacted in the duct orifices. In other instances it is due to cohesion of the margins of the outlet. A similar condition in the parotid duct is known, but is less common. Aside from this, certain other cysts originate from minute beginnings in and about the floor of the mouth, being due to dilatation of the mucous glands, particularly one near the tip of the tongue, sometimes known as _Nuhn’s gland_. Dermoid cysts in this locality are not uncommon. Formerly cysts of the floor of the mouth were described as _ranula_.
_Pancreatic cysts_ correspond in large degree to salivary cysts, the pancreatic duct becoming dilated by retention when its orifice is obscured; and, indeed, the condition has been referred to as _pancreatic ranula_. Sometimes the canal is dilated in distinct portions, so that the condition resembles a string of cysts; at other times it is the terminal portion which is most enlarged. Such cysts attain large size and contain mainly mucoid material. Examples have been reported showing that they have attained a capacity of two gallons.
In the mesentery there sometimes develop cysts which are known as _chyle cysts_, whose sacs appear to be formed of separate mesenteric layers, their cavity being occupied by fluid identical with chyle. Such tumors also sometimes attain great size.
In the eyelids one occasionally meets with cystic dilatations of the lacrymal ducts. These are known as _dacryopic cysts_ or _dacryops_. Fistulas result when they are opened through the skin, and if meddled with at all they should be radically extirpated.[13]
[13] In the treatment of cysts, as of many abscesses (_e. g._, those of the gland of Bartholin), it will be of advantage to empty the cavity through a small trocar or needle and then to fill it with melted paraffin, as suggested by Pozzi. When it has thus been distended it can be dissected out with much more deliberation and more easily than would be otherwise possible.
=Pseudocysts.=--In his elaborate work on tumors Sutton has made a distinct classification of pseudocysts, which lack some of the characteristics of genuine cysts, yet, nevertheless, are entitled to consideration in this place. Among these are included _intestinal diverticula_ and _vesical diverticula_, in either of which instances hernial protrusions of the mucous membrane through the outer coating of the bowel or of the bladder occur, thus forming pouches. These are common in the bowel, rare in the bladder; especially in the former locality they are often multiple. This condition is often referred to as _sacculation_, and sacculation of the bladder may even be confounded with true urachus cyst. They are of little consequence so long as foreign materials, such as feces, urinary calculi, etc., do not lodge in them. But they occasionally cause serious trouble. Diverticula have been mistaken for appendices, while diverticula from the bladder have been encountered in hernia operations.
_Pharyngeal diverticula_ give rise to rare but most interesting tumors. It is well known that the branchial clefts, which in early fetal life connect with the pharynx, are sometimes not completely closed, and that a portion of one may persist abnormally, giving rise to a condition known as the _pouch of Rathke_. There may also occur sacculation of the pharyngeal wall where it joins the esophagus, or hernial protrusions, especially in Rosenmüller’s fossa.
Cystic dilatation of Rathke’s pouch occurs near the upper part of the pharynx, and may attain the size of a marble. Hernial pouches are seldom mistaken for cysts, and are of importance mainly because of the fact that food or other foreign material gathers and lodges in them. Most of the other cystic abnormalities of the pharynx pertain to dermoids, and will be considered shortly. In a general way, these pharyngeal tumors have been grouped as _pharyngoceles_.
Similarly in the _esophagus and trachea hernial protrusions_ occur, and lesions closely resembling retention cysts may be seen.
_Synovial cysts_ (_i. e._, those containing synovial fluid) may arise (1) by protrusion of synovial sheaths, (2) by distention of bursæ in the vicinity of joints, or (3) by hernial protrusions of joint membranes. They are often met with in connection with the larger joints, more particularly about the knee. In this way tumors as large as goose-eggs may be formed, while their location may be so shifted that they present themselves in perplexing ways. To that form produced by hernial protrusion of the lining of a tendon sheath has been given the name _ganglion_.
The simple ganglion is frequently seen on the back of the wrist, and, while it is always connected with the tendon sheath, it undoubtedly often connects with the synovial membrane of the carpal joints. The compound ganglion, so called, is a much more serious and extensive affair, being one which has prolongations in two or more directions, and containing peculiar bodies, known as _melon-seed bodies_, which appear to be fibrinous concretions worn round and smooth by attrition. These are present sometimes in enormous numbers. (See Tuberculosis of Synovial Structures,