The authors describe three cases of megspondylodysplasia, an original syndrome first described in 1972. This congenital lesion is associated with severe kyphoscoliosis, multiple hemimelic enchondromatoses of the spine, hands, feet, knees and hips and hypertrophy of half of the body. In the discussion, differentiation between this syndrome and other diseases such as Ollier's or Mafucci's disease is described. Surgical correction on such a severely deformed spine is dangerous to the spinal cord.