The solitary osteochondroma, a common pediatric bone tumor, is a cartilage-capped exostosis. Hereditary multiple exostosis is an autosomal dominant disorder manifested by the presence of multiple osteochondromas. Linkage analysis has implicated mutations in the EXT gene family, resulting in an error in the regulation of normal chondrocyte proliferation and maturation that leads to abnormal bone...

We report two cases of vertebral osteochondroma. In one patient a solitary cervical lesion presented as entrapment neuropathy of the ulnar nerve and in the other as a thoracic tumour associated with hereditary multiple exostoses producing paraplegia. We highlight the importance of an adequate preoperative evaluation in such patients.

A case of a mentally retarded male patient with associated physical abnormalities resembling the multiple exostoses-mental retardation syndrome (MEMR, Langer-Giedion or Ale-Calo syndrome) is reported. The patient represents one of the most severe examples of this condition; he also has a triphalangeal thumb with double distal phalanges, a feature not reported previously.