RELATION OF VESICULAR MOLE TO CHORION CARCINOMA 149 
buds. These buds are somewhat typical in appearance. The nuclei are seen to 
be all massed together in the centre, forming what appears under the low power 
to be the dense deeply-stained nucleus of a giant cell. But on closer examination 
it is seen to be composed of a number of coarsely granular nuclei or very 
irregular shape, crowded together, and fitting into one another. 
In other places the epithelial masses present a more reticulated appearance. 
Large oval spaces are seen between the cells, suggesting an exaggeration of the 
vacuolation process which takes place normally in the plasmodial cells of the 
trophoblast. According to Peters, two forms of degeneration occur physiologically 
in the trophoblast, namely, vacuolation and condensation, and it appears to me that 
in vesicular degeneration of the chorion, these two processes are carried on in a marked 
degree, giving rise to the network of syncytial cells on the one hand, and to buds of 
the same tissue on the other (see Ligs. 8, 9, and 10, Plate X_). 
Almost more striking, however, than this external proliferation is that which 
I have remarked in many of my sections, namely, an invasion of the stroma of the 
villus by the epithelium. This is a point of great interest, shewing as it does the 
power of the foetal epithelium to penetrate into mesoblastic tissue, thereby causing 
its destruction. In places the ingrowths of epithelium give the appearance of a 
transverse section of a tubular gland, lying embedded in the stroma, completely cut 
off from the outer investing layers. The inner layer of this glandular looking 
structure is formed of deeply stained flattened nuclei, arranged round the lumen, 
while outside these, cubical and cylindrical cells are seen, having a definite cell outline 
and possessing oval nuclei. 
These are not seen in all sections of vesicular mole, but when thev are present 
they are a sign of great importance as indicating undue activity of the epithelium. 
It has been said by some observers that it is possible from the microscopical 
appearances in vesicular mole to foretell the occurrence of chorion carcinoma. Whether 
this be so or not has yet to be proved, but it is interesting to note that in the one 
case of vesicular mole I have to record, which afterwards developed this condition, 
the sections did present some unusual features. 
To the naked eye, the vesicles were of small size and surrounded by large 
masses of blood clot. Microscopically the stroma of the vesicles was seen to be 
completely disorganized, nothing remained of the myxomatous tissue, its place being 
taken by a homogeneous structureless network which stained a dark blue with 
haematoxylin. The outer covering, however, shewed great activity. Like the 
appearances described above, the nuclei were greatly increased, but the protoplasm 
of the syncytium appeared shrunken and very granular, as though undergoing some 
degenerative change. 
Budding of the syncytium was very marked, but differed from that usually 
seen, in that the protoplasm formed a thin shell-like enveloping membrane, inside of 
