HYDATIFORM DEGENERATION IN UTERINE PREGNANCY. 215 



a case in which a hydatiform mole 14 by 9.6 by 4.3 mm. was aborted in the 

 twelfth month after the cessation of menstruation. Although Sternberg included 

 4 cases from other countries among these missed-abortion moles, viz, those o 

 Sheil (undated), Ferguson (also undated), Colorni (1908), and Gaifani (1908), one 

 can hardly doubt that more cases could be added. Since the case of Sheil was one 

 of twin pregnancy, in which one conceptus became hydatiform, it is njt at all 

 unlikely that some other cases among this rather small series of twin pregnancies 

 accompanied by hydatiform degeneration may belong in this category. 



Mayer (1911) also emphasized the fact that, although instances of retention 

 of fetuses are very common, instances of retention of hydatiform mole are very 

 rare, only a few cases having been recorded. Maj r er referred to 2 cases by Kehrer, 



3 of Borland and Gerson, and 1 case of Lange, and reported 4 of his own. These 



4 were found among 10 cases of hydatiform mole, an incidence of retention of 

 40 per cent. They are interesting, especially in connection with the observation 

 of Briggs (1912) that, contrary to current belief, uterine enlargement often is not 

 beyond the normal. Mayer reported that this enlargement was too great in but 

 1 of the 4 cases, and that retention lasted as long as 4 to 5 months. 



At least 3 of the cases of hydatiform mole among those originally recorded 

 as such in the Carnegie Collection belong among retained specimens, as the illus- 

 trations alone suggest. But a fair percentage of detached chorionic vesicles 

 included in the list of cases here reported undoubtedly also was retained after the 

 cessation of growth, and it is for this reason that I further emphasize the fact that 

 the uterine volume in a considerable percentage of these cases also, instead of 

 having been too great for the duration of the pregnancy, unquestionably was too 

 small. This is well illustrated by the histories of specimens Nos. 70, 323, 1640, 

 and 1926, and by the specimens themselves. 



The average menstrual age of 51 of 112 uterine specimens of hydatiform 

 degeneration in which the data were available was 66.6 days, or 2% months. 

 As will be seen, this is a far lower average age than heretofore reported, a difference 

 which explains itself from what has already been said. It is interesting that the 

 average menstrual age of 5 of the 8 specimens in the Carnegie Collection originally 

 classed as hydatiform degenerations is 168.2 days, or 1}/2 times as great, thus 

 being in substantial agreement with the usual results. Three of these 5 are large 

 specimens, the fourth measures 40 by 20 by 15 mm., and the other is composed 

 of small fragments contained in material from curettage. From this alone it 

 follows that the menstrual age is a very uncertain guide, especially to the size 

 of a hydatiform mole. 



It may seem superfluous to add anything to the good descriptions of the gross 

 appearance of the typical hydatiform mole found in the literature. Such cases are 

 so characteristic that even a novice can recognize them at sight. Yet if the findings 

 reported here are reliable, or even approximately so, it nevertheless must be evident 

 that, in the past, the great majority of specimens of true hydatiform mole have 

 remained unrecognized merely because they did not happen to present the cus- 

 tomary, well-known picture to the unaided eye. Small chorionic vesicles, such as No. 



