The pathology, known as cherubism or familial fibrous dysplasia of the jaws, is a fairly rare condition (although not unheard of) and congenital. It shows itself at about the age of three, usually in males. Multiple benign tumours known as giant cell granulomas - appear on the mandibula and also, on occasions, on the upper jaw. As a consequence, an increase in the size of these bone structures takes place which, in turn, produces facial deformity. In more than 90% of these cases the defect is not particularly noticeable and a normal life can be led; in fact, many scientific articles discard surgery as normally the ailment stabilises on the growth coming to an end. Infrequent case The child treated at the University Hospital showed an infrequent case of cherubism. An explosive growth of one or more of the granulomas caused the tumour to reach 10cm diameter and 400gr weight in a few months. After confirming the diagnosis the decision was taken to carry out surgery, given that the infirmity was continuing to evolve, which could have caused serious psychological damage to the child. The operation involved the extirpation of the mandibula from one end to the other, as it had been completely affected by the tumour. Then a transplant from the fibula bone was substituted, while maintaining the growth factors in the ankle to avoid unwanted consequences for the limb. Unlike a graft, a bone transplant is accompanied by its own artery and vein, and these are joined to arteries and veins in the neck, thus ensuring vascularisation from the start. Moreover, a bone graft, not having vascularisation, is very sensitive to infections and thus increases the possibilities of failure. Evolution The postoperative stage was successful and the child can lead a normal life. Currently he talks and eats perfectly and can walk and do sports like any other child of his age. Also, any scars are inside the mouth, which means the cosmetic aspect is greatly enhanced. After the bone transplant the next step is dental implanting, a procedure that will take place in two stages.