Presentation
On the first set of radiographs the patient is 2 years old and asymptomatic. On the second set of radiographs the patient is 10 years old, in a routine pediatric's consultation, although he has reported occasional minor hip pain.
Patient Data
Note in these set of images that the patient presents osteochondromas across several bones of his body.
- Both femurs have osteochondromas. Note that they are not symmetrical, whereas the right one protrudes from its medial aspect and grows medially and superiorly; the other, on the left femur, arises and directs itself posterior and superiorly.
- The tibias' exostosis are sessile. Both of the tibias present with osteochondromas on their proximal diaphysis, but only the right one has an osteochondroma emerging from its distal diaphysis.
- And, quite discrete, there is a small osteochondroma at the medial surface of the right fibular distal diaphysis.
- The hip's alterations are more subtle than the ones just described above. First of all, pay attention to the slight different femurs' heads and necks morphology. Then, notice how much more horizontal both the proximal femoral physis are, which might be an early sign in the immature skeletal.
- There is a pedunculated osteochondroma protruding itself from the outer surface of the patient's left scapula.
- Finally, regarding the forearms, notice that only the right one is affected. There is an exostosis protruding from the ulnar middle diaphysis, and another one arising from the radius distal diaphysis.
It is quite obvious that the osteochondromas grew during the 8-year interval, just like the patient himself also grew and developed. Some of the interesting features worth commenting are:
- Firstly, the knees - the previously presented exostosis increased in dimensions and new bone lesions raised from the fibulars' heads and proximal diaphysis.
- Secondly, the hip and femurs - notice the metaphyseal bulging with a coxa valga deformity of both proximal femurs, besides the prominent undertubulation. Although it is not so evident, there is also the Erlenmeyer flask deformity.
- Thirdly, the ribs - although it is not easily seen, there is a pedunculated osteochondroma developing from the inferior surfaces of the eighth and ninth left ribs.
Case Discussion
Hereditary multiple exostoses occur primarily in the proximal metaphysis of the long bones, although a wide range of osteochondromas skeletal distribution has been found over the last decades. The patient in this case not only presented with osteochondromas throughout his appendicular skeleton (femurs, tibias, fibulas, ulnar and radius bones, scapula) but also involving the axial skeleton (ribs).
Whereas it has been observed that the typical distribution is bilateral and symmetric, some authors also reported the possibility of a unilateral predominance. Interestingly, the patient above presented both features.
Usually, osteochondromatosis is quite a benign condition. However, sometimes it may cause problems, either due to their size/location / considerable number or because of their association with growth plates, consequently affecting skeletal elongation and function, leading to growth retardation and malformation. Furthermore, there is still another possibility, which is much more serious, as it regards the eventuality of the exostosis undergoing malignant transformation into chondrosarcoma.
Therefore, it is important to maintain long term care and follow up.
Contributed by Dr. Guilherme Pioli Resende M.D. and Dr. Sergio Lopes Viana M.D.
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