The authors report a case of chondrosarcoma in a 14-year-old female patient with multiple osteochondromatosis who has sought medical assistance complaining of a tumor on the left coxa. CT images of the affected limb have demonstrated osteodestructive lesion on the superior third of the left femur. The diagnosis has been made through a review of the biopsy slide from the service of origin of the patient, confirming the finding of a grade I chondrosarcoma in a chondromatous lesion. Disarticulation of the femoral neck was made because of the large extent of the lesion in muscular groups, subcutaneous cellular tissue and skin. The literature shows a wide variation in rates of malignant transformation of exostosis in patients with this disease, and this is a significant complication in patients affected by this disease.

Keywords: Chondrosarcoma, Multiple osteochondromatosis, Computed tomography, Femur