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.