Various opinions have been broached to account for the existence of spermatozoa in the encysted form of hydrocele of the testicle. The explanation which seems to me the most reasonable and probable, is that which I offered shortly after the occurrence of sper matozoa in encysted hydroceles was first dis covered*, viz. that their presence is probably owing to the accidental rupture of a seminal canal, and the escape of its contents into the cyst of an existing hydrocele. The close proximity of the efferent tubes, the slight tex ture of the ducts and delicate walls of the cyst, and the liability of the part to contusion and injury, when a swelling even of moderate size exists, seemed to me to favour this view. The circumstance that spermatozoa are never found in very small cysts show that they are not originally formed there, but are a subsequent addition to their contents. Since my attention has been drawn to this subject I have investigated the history of the cases of encysted hydrocele containing spermatozoa, which came under my notice. In nearly all instances the patients assured me that the swelling had gradually formed after an injury to the testicle ; and in two cases it was clear that a small cystic swelling had long existed in a stationary state, but after a slight blow had begun to enlarge. I strongly suspect that, in these cases, a duct had been ruptured by the contusion, and that the irritation con sequent on the injury, and perhaps on the addition of such lively bodies as spermatozoa to the fluid contents of the cyst, had led to its further development. I have, it is true, failed in establishing the fact of a communica tion between the duct and the cyst by ana tomical examination. In two instances of large encysted hydrocele containing sperma tozoa, which I had an opportunity of examin ing, I injected the vas deferens with coloured size, but the duct was so clogged with semen that the fluid could not be made to reach the head of the epididymis, to which the cyst was attached. In a preparation of large encysted bilocular hydrocele containing spermatozoa, shown me by Mr. Busk, the vas deferens had been injected with mercury, but none of the metal reached the upper part of the epididymis. The cyst evidently arose from the head of the epididymis, and was embedded a little in its substance. In these cases no opening com municating with a duct could be discovered on examination of the cysts, but this is not surprising, since the communication must be extremely minute, so as readily to escape detection, or it may even have been obliter ated.
Spermatozoa are stated to have been found in some two or three instances in fluid re moved from the tunica vaginalis. It is not improbable that these cases may have been encysted hydrocles mistaken for simple. The diagnosis is sometimes very difficult, and in the ease of the cyst examined by Mr. Paget,* this error was made before death by a hospital surgeon. I have, however, found spermatozoa in the sac of the tunica vaginalis, and the fol lowing case will account for their presence. A man aged fifty-four died in the London Hospital of disease of the kidneys, of one of the ureters, and of the bladder, which appeared to be consequent on a severe blow on the loins about six weeks before. The tunica vaginalis of one of the testicles contained two ounces and a half of slightly opaque fluid, in which a few spermatozoa were found. There were three small cysts containing fluid immediately connected with the epididymis, and also at one spot an irregular ragged membranous appear ance, evidently caused by the rupture of a cyst. It is most probable that the spermatozoa had escaped from this cyst, which may indeed have been burst at the time of the injury. I have examined the fluid from the tunica vagi nalis in a large number of instances without finding these bodies, and I believe their occur rence in the common form of hydrocele to be extremely rare.
Diffused Hydrocele of the Spermatic Cord.— Mr. Pott has given an admirable account of this affection, under the denomination of hy drocele of the cells of the tunica communis.t It has likewise been particularly described by Scarpa.* The disease is of the nature of simple oedema, a watery fluid being diffused throughout the areolar tissue connecting the vessels of the spermatic cord, and enclosed in a sheath, which is invested by the musculo aponeurotic structure of the cremaster muscle. When the complaint has lasted some time, the sheath is found more or less thickened. The areolar tissue within is infiltrated with a limpid albuminous serum of a white or yel lowish colour, which flows out in the course of the dissection. The cells infiltrated with serum are converted into large vesicles, some of which are big enough to admit the tip of the finger. These cells are larger and more delicate towards the base of the swelling, where they sometimes disappear altogether ; so that there is only one considerable cavity at the lowest and more depending part. The base of the swelling corresponds to the point at which the spermatic vessels join the testicle, and at this part a dense septum cuts off all communication with the tunica vaginalis. In some instances the effusion extends along the cord into the abdomen, as in a remarkable case related by Mr. Pott. In the annexed figure of
this affection, (fig. 643.), taken from Scarpa, the envelope of the cremaster is laid open, posing the pyramidal swelling enclosed in its sheath of condensed areolar tissue. The tes tide and tunica vaginalis are seen below it. In general anasarca the areolar tissue of the spermatic cord, as well as of the scrotum, is frequently distended with serum ; but cedema of the cord alone is a very rare affection. Sir A. Cooper makes no allusion to it, and Mr. Pott, to whom we are indebted for so good and accurate a description of this species of hydrocele, probably met with a greater num ber of cases of it than have occurred in the practice of any surgeon since his day.
Encysted Hydrocele of the Spermatic Cord.— A cyst containing fluid may be developed in the loose areolar tissue of the spermatic cord. The cyst is formed of a thin transparent membrane, possessing the ordinary characters of a serous membrane, and contains generally a limpid aqueous liquid, having little or no albumen, but sometimes a straw-coloured serum similar to the fluid of simple hydrocele. It is of an oval form, and its size, though variable, seldom exceeds that of a hen's egg, and is usually smaller. It is loosely attached by areolar tissue to the vessels of the cord which are situated at its back part, but be come separated and displaced by it. The cyst is invested by the common integuments, super ficial fascia, musculo-aponeurotic sheath of the cremaster muscle, and fascia transversalis. It may occur either immediately above the tes ticle, in the middle of the cord, or just below the abdominal ring, and even within the in guinal canal. Usually there is a single cyst, but occasionally several are developed, and a chain of them has been formed along the cord. The cyst and its contents are liable to changes consequent upon inflammation. Encysted hydrocele of the cord appears to originate, in general, in a partial or imperfect oblitera tion of the prolongation of peritoneum drawn down at the period of the transition of the testicle. I have already described the different appearances presented by the remains of this prolongation, which, it has been remarked, sometimes consists of a single cyst, or of two or more sacculi, moistened by a serous fluid. When this fluid accumulates in any quantity, an encysted hydrocele is the result. Such is obviously the mode of origin of this affection when occurring in infants, and no doubt in adults it generally originates in the same way. M. J. Cloquet has remarked that the remains of the peritoneal process accompanying the testicles in their descent were met with in male subjects of all ages, and he mentions as a singular circumstance, that they were nearly as frequently found in the old as in the young subjects.* My own dissections agree with the observations of this accurate anatomist. In the museum at the London Hospital there is a preparation showing the tunica vaginalis continued for about two inches up the cord, and, immediately above it, an encysted hydro cele, which was taken from an adult subject. In dissecting the body of a man, aged eighteen, I found an encysted hydrocele of the cord above the testicle in close contact with the tunica vaginalis. Immediately above this cyst, but quite distinct from it, there was a narrow and empty serous sac three inches in length, with a contracted neck, and communicating with the abdomen. They are figured in the accompanying engraving, with the hernial sac laid open, and part of the parietes of the encysted hydrocele cut away to expose their interiors. The position of the testicle is so changed that its anterior border is directed downwards. In the examination of the body of a man who died of disease of the heart, I found on the right side a thickened and empty serous pouch, extending for about an inch and a half below the external abdominal ring. Directly below it was an independent cyst, capable of containing a walnut, similar in structure to the hernial sac, but lined by a thin false membrane. The tunica vaginalis, which was healthy in structure, extended up the cord as far as the cyst, from which it was separated by a thick and firm partition. In opening the body of a sailor who died with ascites, I noticed at the internal ring a small, delicate, transparent, pedunculated cyst, not larger than a nut, projecting into the cavity of the abdomen. In the spermatic cord, there was a large serous cyst, which extended into the inguinal canal, and contained a small quantity of transparent fluid. A small orifice at its upper part opened into the peduncu lated cyst, which proved to be a process from the cyst in the cord. In fig. 644., I have given a representation of an inguinal hernia, combined with an elongated encysted hydro cele of the cord ; and in fig. 647., a repre sentation of an encysted hwmatocele of the cord, in which the tunica vaginalis remained unobliterated as far up as the cyst, whilst a hernial sac is situated immediately above it. These dissections confirm the view taken by Sir A. Cooper, and now commonly adopted, of the mode of origin of encysted hydrocele of the spermatic cord in the adult.