270 REPORT OF THE HARVARD AFRICAN EXPEDITION 
periarterial gummata was the round cell with occasional spindle-shaped epi- 
thelial cells. There were no giant cells nor polynuclears. There was no evidence 
of caseation or necrosis. No cartilage nor bone had formed. The blood vessels 
were extremely numerous for a tendon. The majority were of the single layer 
capillary form. The lumen of even the smallest was open and the lining appeared 
uninjured. No vessel was seen of sufficient size to show evidence of the infiltra- 
tion of the coats. There was no formation of a fibrous connective tissue wall 
about the mass. It was apparently a diffuse process. The histopathological 
diagnosis was ‘‘granuloma, probably syphilitic.”’ 
A study of the other literature upon the subject of juxta-articular nodules 
also reveals the fact that in a great many of the cases the histological changes 
are very varied and that the histological picture described by different authors 
is not uniform. 
It is also not clear that the differences, in the various publications regarding 
the histological changes, can be explained according to the duration of the lesion 
in different cases. Jessner’s description of the lesions he observed, when com- 
pared with some other published reports, especially emphasizes this fact. There 
is, however, a similarity in the histological picture that he describes to that ob- . 
served by Jeanselme and ourselves. Jessner also found xanthoma-like cells in 
the inflammatory areas in the lesion he examined and demonstrated the presence 
of cholesterin by chemical reactions. He considered this lesion to be of syphilitic 
origin and points out that this is the first time cholesterin has been found in such 
a case, though it is well known to occur in other cases of tropical juxta-articular 
nodules. 
In many of the cases reported by other investigators, the tumors have not 
been removed, cultures not made and the lesions not studied histologically, so 
that they are not of special value from the standpoint of aetiology. Nevertheless, 
from a study of all the material available, certain features regarding the aetiology 
of these nodules appear to have been established. 
It is quite obvious that juxta-articular nodules often result about localities 
which are frequently subjected to pressure and to light blows or bruises often 
repeated. It also seems not unlikely that under certain conditions, they may 
result from different forms of mechanical irritation, just as other true neoplasms 
may, and that in some instances they may be onchocercal in origin and in others 
framboesial or syphilitic. In the last instance, syphilis or yaws may act as a 
predisposing factor among people or races with especial tendency or diathesis 
to the abnormal proliferation of fibrous tissue. However, it is difficult to explain 
the peculiar inflammatory lesions by such a hypothesis alone.! Also, while 
racial tendencies may be a partial factor in their production, it should be borne 
in mind that although these lesions are very common in parts of Africa, they do 
occur in many other parts of the tropical world. There is nothing entirely 
pathognomonic about the tumors, but the changes we have described consisting 
' De Quervain has gone so far as to suggest there is in this condition a special strain of spirochaete 
for connective tissue, a fibrotropic strain weakly virulent and exerting its action in a locality subject 
to trauma. 
