Paper - A study of the causes underlying the origin of human monsters 13

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Mall FP. A study of the causes underlying the origin of human monsters. (1908) J Morphol. 19: 3-368.

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1908 Mall TOC: Historical | Double Monster | Lithium embryos | Salts of potassium and heart | Spina bifida and anencephaly | Cyclopia and club-foot | Pathological ova | Twin pregnancies | Unruptured tubal pregnancies | Ruptured tubal pregnancies | Amnion Destruction | Moles | Pathological ova umbilical cord and amnion | Second week | Third week | Fourth week | Fifth week | Sixth week | Seventh week | Eighth week and older | Specimens and figures | Plates | Historic Papers | Franklin Mall

A Study Of The Causes Underlying The Origin Of Human Monsters

Pathological Ova and Moles containing an Amnion with the Embryo destroyed wholly on in great part

Under the last headings specimens were described in which most or all of the embryonic mass was destroyed, leaving the chorion to outline the coelom. Such specimens are numerous and no doubt give rise to most of the solid moles. All other specimens in which the embryo is destroyed are of necessity those in which the amnion is formed, sweeps through and obliterates the coelom in its development and lines the chorion. It is evident when these two groups of specimens are considered that the first must arise from ova of the first month, for in them the amnion is small, and the second group, from older ova after the amnion has reached the chorion.

In general, the older the embryo is when it begins to become pathological the more resistant it is, and it follows that the younger the specimen the more easily it is destroyed. Probably this is the reason why an ovum without an embryo rarely contains an amnion. No matter how large the specimen may be, if the interior of the chorion is not lined by the amnion it is safe to say that the pathological changes in it began during the first month (probably during the first fortnight) of pregnancy. In case the disease of the ovum, which is usually due to endometritis, begins during the second month of pregnancy or later, the amnion is well formed, usually continues to develop, and reaches the chorion. Ova of this sort, which constitute the major portion of my specimens, contain embryos more or less degenerated, and at best form vesicular moles with the remnants of embryos within them. In a few of them, however, the embryos are destroyed, leaving only the umbilical cords, and in two or three specimens they were also destroyed, leaving only the chorion and the amnion.

In all of these ova the cavity of the amnion is retained, and they do not appear to develop into solid moles, but may con tinue to grow on indefinitely like those of the group given in Table III. No.


I30 35 37

I98 32


342 377“ 93


257 77

379 379



mm. 7 X3 X3 15 x1ox6

35 25 1: 18x15 95 [3o]%V?a1nut

3ox2oxzo 3ox22x:4



55x4-0340 7_ox4ox3o

roo x60 x 60

x 2 5 x r 5 Granu at embryo to wks. 35 of the 4th week

Embryo mass.


No. 1.]

M 11121 . . . . 822$ Chonon. ‘ V1111. Syncytiuxn.

1_nm. Amnion only

7x2 6x2 2x2 7 g_x2 Amnion only


-5 Amnion only

Embryo 5 mm.

14x2 rxo.25



days i


4 7o <7)

4 wks.





Invaded by 1eucocytes and syncytium.



Invaded by syncytium.

Atrophic and invaded by. sIyncytium and eucocytes.


Invaded by 1euco'cytes and syncytium.



Atrophic and fibrous.

Normal. Normal." Fibrous .

Invaded by 1eucocyt_es and syncytium.






Invaded by 1eucocytes and syncytium.

Normal (?)




Increased .


Increased .

Diminished . Increased and necrotic .

I shall first consider those ova in which the embryo, or embryo and cord, has been destroyed, leaving only the amnion, and will leave the ova or moles with pathological embryos to follow. There are many of them, and when they are classified in weeks they tell a continuous story.

Table IV gives the list of ova in which the amnion is retained, with such other data as I have been able to collect. Unfortunately, the data relating to the age of the specimens are very incomplete. However, it is possible to connect the specimens in a satisfactory way if we begin with those which have remnants of the embryo attached to the cord, and gradually proceed to those in which the cord is destroyed entirely, leaving only the amnion and the chorion.

In general, the size of the chorion and cord do not correspond properly with each other, showing that either one or the other has been retarded in its growth. In specimens Nos. I30 and 32, for instance, the embryo masses are of about the same size, representing cords of the second month, but one is from a small and young ovum and the other is from a large and much older one. It is fair to assume that the embryo in No. 32 was destroyed when the ovum was as small as No. I 30 is at present.

Table IV gives a list of the specimens with all stages of destruction of the embryo after the amnion is well formed, leaving only a portion of the embryo, or, in extreme cases, the umbilical cord alone. In a few of the specimens the cord is also destroyed and in them the chorion is lined simply by the arrmion. The villi of the smaller ova of this group appear quite normal, and for this reason I have been inclined to think that in them the primary cause lay in the embryo itself, and that in the older stages the changes found in the chorion were of a secondary nature. Further investigation, however, may reveal the same early changes in the neighborhood of the villi here as are found in the specimens in which the embryo and amnion were destroyed during the first four weeks of pregnancy (Table III). Here also the earlier specimens, those with numbers lower than I50, did not show any signs of endometritis, but since then nearly all of the specimens collected have been hardened in formalin instead of being first washed in water or in weak alcohol, as uninstructed physicians do so frequently. Further observation with well preserved specimens will also probably show signs of endometritis in specimens of this group, less than 30 mm. in diameter.

The embryo is entirely destroyed, leaving only the amnion in a very small per cent of pathological ova. Usually the embryo continues to grow slowly in an irregular fashion, but sometimes there is a destruction of some of its parts. In most of these cases, however, the circulation has been established and the coelom is pretty well obliterated, thus eliminating the importance of the magma reticulé. Therefore primary changes in the embryo are clearly associated with the blood and the vascular system, and this naturally affects the embryo more than it does the other structures.

I shall consider No. 37 first, because it still contains the outline of a portion of the embryo. The atrophic head of the embryo is seated upon a very small cord and these are surrounded by the amnion. The umbilical vesicle is attached to the side of the cord, but does not reach into the embryo.

The central nervous system is very rudimentary, and the heart, liver, myotomes and lower end of the body are wanting. The lower jaw is still recognizable, and from it two arteries pass over into the cord. The single vein of the cord ends blindly just below the rudimentary branchial arch. The size and degree of development of the embryo places it in the beginning of the third week, when no doubt its destruction began. The chorion, however, belongs with those of the fourth or fifth week, which indicates that the process of atrophy has been under way for a week or two.

In specimen No. I 30 the embryo is reduced to a small mass of round cells showing no structure whatever. The umbilical cord is filled with its usual blood-vessels, showing that an embryo had been present at an earlier date. The whole is inclosed in a relatively small amnion, which doubt protected and held together what little of the embryo there was left. The cord extends to the chorion in the wall of the amnion, showing why the yolk sac, described on page 80, broke away so early. The amnion fills only half of the coelom, the remaining portion being stuffed with a dense mass of magma. reticulé.

No. 257 is similar to No. 130, inasmuch as both of them have small bodies upon the end of the cord, representing the remnants of the embryo. However, it is much older, the chorion being larger and many of the villi having undergone fibrous changes are atrophic. The body at the end of the cord is not the remnant of the embryo, but simply its continuation, with the umbilical vein running through it. Although this specimen might have passed for a normal one when examined superficially, more careful examination showed that the decidua was infiltrated with leucocytes. The chorion is lined by the amnion, which is mostly adherent and contained a clear fluid. No remains of a disintegrated embryo were found within the amnion.

Another specimen with a small remnant of the embryo is No. 342, which is from a tubal pregnancy. Attached to the free end of the cord is a bit of tissue which must belong to the embryo, with a small mound of active cells growing in it. The chorion, amnion and cord have undergone fibrous degeneration.

Nos. 25, 32 and 198 are specimens of simple ova with a naked cord projecting into the amniotic cavity in each case. In No. 198 the amnion is filled with reticular and granular magma intermingled with scattered flakes of the embryo and numerous free cells. The cord is rounded at its free end and its blood-vessels are empty. The mesoderm of the chorion, villi and cord is fibrous, with an excess of spindle—shaped cells scattered through it. Similar stages are shown in specimens Nos. 32 and 25. In both of them the blood-vessels are well filled with blood, and in the first there is an extensive wandering of.blood cells into the surrounding tissue, especially at the tip end of the cord. Here they stain intensely with carmine and suggest very much a section through an ulcerating wound. ‘No. 25 may possibly represent a more advanced stage, inasmuch as the free end of the cord is more rounded.

To what extent a cord may grow, or at least round itself off, is shown in No. 279. The fleshy chorion is composed of villi which seem to be nearly normal, the mesoderm being somewhat hyaline in structure, with a diminished number of nuclei scattered through it. Within there is a large free umbilical cord curled upon itself and rounded at its free end. No doubt the foetus escaped from its membranes before they were expelled. However, I was unable to determine whether this had really taken place. The blood-vessels of the large villi are well developed, indicating that at one time the foetus present must have been pretty large. At any rate, the broken end of the cord became rounded and healed over after the foetus had been broken off.

Specimen No. 77 shows that the free cords are gradually destroyed if the ovum is retained in the uterus long enough. In it the chorion and amnion are both more fibrous than normal. The villi are being invaded by leucocytes and syncytium, giving the secondary changes which are often seen when the mesoderm of the villi has lost its vitality. No remnants of blood-vessels are present in the villi. The cavity of the amnion contains a clear fluid, and on one side there is a small stumpy cord, about one millimeter in diameter, which attaches the amnion to the chorion.

Nos. 334 and 379 may also be considered with this group. No. 334 formed a fleshy mole, with a cavity in its center, 15 mm. in diameter, and contains the fragment of an embryo which must have been fully five weeks -old when it died. The main tissue of the mole is composed of uterine mucous membrane, decidua, blood and pus, with a ramifying chorion in it. The wall of the chorion is infiltrated with leucocytes on its outside and invaded by syncytium from its inside. Had it not been for the fragment of an embryo this specimen would have been grouped in Table III. No. 379 contains a. granular embryo, IO mm. long, which readily fell into pieces upon being handled.

Nos. 77 and 334'show what may become of the chorion and amnion when they are retained in the uterus long enough. The villi are attacked on the outside by leucocytes and syncytium, the cavity of the amnion collapses, or is penetrated and filled, making the mole solid, as is the case in so many younger ova after the embryo and amnion have been destroyed.

Another specimen belonging to this group is No. 93. It came to the laboratory fresh, enveloped in its decidua, and the whole was hardened in ‘formalin. Between the decidua and the ovum there is a layer of blood and fibrin. The main body of the mole is composed of irregular hypertrophied villi with a great amount of blood and syncytium between them. Occasionally the syncytial cells are found in the mesoderm of the main walls of the chorion. The small cavity within is lined with the amnion and is filled with blood. No embryo was found. Nos. I 59 and 369 are similar specimens, since in them the cord is also destroyed entirely. No. 159 is composed of fragments of a mole, the embryo having been lost. However, the fragments are made up of mucous membrane of the uterus, large portions of the chorion and some fragments of the amnion. The mucous membrane is full of small abscesses, and leucocytes have invaded the mesoderm of the chorion and its villi. The syncytium is very active and at numerous points it also has invaded the mesoderm of the chorion and villi. The amnion is hyaline, thickened, curled upon itself, and at points its epithelial layer has proliferated. forming small mounds.

The specimens just described show the fate of ova after the embryo is destroyed, leaving first the cord and amnion and then the amnion alone. Finally the cavity of the amnion is punctured, the ovum collapses and the whole is converted into a solid mole. Specimens of this kind are rare, since most solid moles are formed from ova in which the amnion and embryos were destroyed at a much earlier date.