xiii, b, 2 Maul: Bone and Joint Lesions of Yaws (35 



With the exception of the 2 per cent of cases showing as 

 a swelling over the surface of the bone, the X-ray picture is 

 different from the bone lesion of syphilis, in that: (1) The 

 periosteal proliferation is absent, and (2) the thickening of the 

 cortex of the bone is absent. Also, in the 2 per cent of cases 

 where thickening of the cortex is present, the thickening remains 

 localized, does not tend to extend along the whole length of the 

 bone, and sooner or later shows rarefication in the center of 

 the lesion. 



The bone lesion of yaws may simulate (1) tuberculous or 

 septic central abscess, (2) gumma, (3) hydatic cyst, (4) benign 

 cyst, (5) fibrous osteitis, (6) enchondroma, (7) endothelioma, 

 (8) secondary carcinoma, (9) myeloma, and (10) sarcoma. The 

 differential diagnosis can be made only by combining the radio- 

 graphic appearances with all clinical data, including the history, 

 physical signs, and evidence of disease or tumor in other parts 

 of the body. 



Summarizing the findings in Table I, it is seen that in 20 

 cases of bone lesions in yaws: 



1. The shaft of the bone is the most frequent location of the lesion and 



shows involvement in 80 per cent of the cases. 



2. The epiphyses or articular surfaces are involved in 20 per cent of the 



cases. 



3. The tibia is the bone most frequently involved (40 per cent of this series) . 



4. The order of frequency of occurrence of the lesions in the other bones 



is as follows: 



(a) Tarsal bones, 40 per cent (75 per cent of these lesions occur 



in the os calcis). 



(b) Fibula, 35 per cent. 



(c) Phalanges of feet and hands, each 30 per cent. 



(d) Metatarsal bones, metacarpal bones, and radius, each 20 per 



cent. 



(e) Patella and humerus, each 15 per cent. 

 (/) Femur and ulna, each 10 per cent. 



(g) Carpal bones, ribs, sternum, and pelvic bones, each 5 per cent. 

 (h) In the bones not mentioned no lesions were found. 



5. There is no constant relation of the location of the external lesion to the 



bone lesion. 



6. The order of frequency of occurrence of the lesions in the joints is as 



follows: Knee, finger, ankle, and elbow. 



7. The lesions are multiple in 75 per cent of the cases, the greatest number 



being one hundred thirteen. 



8. The time between the appearance of the primary lesion and bone lesions 



varies from six months to nine years, with an average of two and 

 eight-tenths years. In this series 45 per cent of the cases showed bone 

 lesions one year; 15 per cent, two years; 5 per cent, three years; 10 

 per cent, four years; 5 per cent, five years; 15 per cent, six years; 

 and 5 per cent, nine years after the appearance of the mother yaw. 



