308 STUDIES ON PATHOLOGIC OVA. 



"The core of the villus gradually breaks down and disintegrates. While this process 

 is taking place we often see scattered through the stroma of the villus large protoplasmic 



cells These cells, which I have repeatedly seen in the villi of pathological ova, 



may be a type of wandering cells; at any rate, when the villus is being invaded by the 

 leucocytes and trophoblast it might be thought that they arise from the latter, but this 

 is improbable." 



It is of particular interest in this connection that Virchow (1863) stated that 

 Schroeder van der Kolk (1851) had concluded that large, clear cells in the stroma 

 of the villi, later classed among the "physaliphores" by Virchow, occurred too 

 frequently to be correlated with hydatiform degeneration. This suggests that the 

 so-called Hofbauer cells were known since the early days of cytology, and that 

 some one must have noticed, even at that early date, that they were very common 

 in some hydatiform moles. Whether or not this was van der Kolk himself 

 I am unable to say, but that Hofbauer cells are especially numerous in some 

 cases of hydatiform degeneration is undoubted. But it does not therefore follow 

 that they are constantly present in this condition. Large numbers of Hofbauer 

 cells were present in 17 out of the 61 cases of normal and pathological chorionic 

 vesicles in which they were especially studied. Of these 17 cases, 14 were later 

 independently identified as showing hydatiform degeneration, and the other 3 were 

 considered as possibly such. In other words, every case of this series in which the 

 Hofbauer cells were numerous was one showing hydatiform degeneration of the 

 villi. It also is true, however, that 34 cases containing but a few or some Hofbauer 

 cells were not identified as being hydatiform moles, although 3 cases containing 

 small numbers of these cells were so recognized. Moreover, not a single case of 

 this series of 61 specimens which contained no Hofbauer cells whatever was later 

 identified as showing hydatiform degeneration. 



Somewhat similar evidence was afforded by the study of 22 cases in the 

 protocols of which Mall had previously noted that Hofbauer cells were present. 

 Of these 22 cases, 13 were later identified as showing this degeneration. However, 

 since a total of 153 cases of hydatiform degeneration were identified among 315 

 of those classed as pathologic among the first 1,200 accessions in the Carnegie Col- 

 lection, it is evident that the presence of Hofbauer cells was especially noted in 

 but a relatively small percentage of this series. Of 30 cases containing Hofbauer 

 cells in sufficient numbers to attract especial attention in the course of a routine 

 examination made for other purposes, 17, or 56.6 per cent, were later identified 

 as instances of hydatiform degeneration. Since the 61 cases in the first series were 

 examined especially for the purpose of study of Hofbauer cells, the higher per- 

 centage of correlation observed in this series may be due partly to this fact. At 

 any rate, that such a correlation exists seems to be quite clear, although I do not 

 conclude that the two conditions necessarily or invariably are associated. 



It is interesting that Pazzi (1908 a ) considered a distrophy of the connective 

 tissue with the development of cellular elements "not very well differentiated, but 

 like the plasma cell of Hofbauer," as the initial and pathognomonic change in 

 hydatiform degeneration. Pazzi further stated that the plasma cell of Hofbauer 



