We present a lethal skeletal dysplasia characterized radiographically by severe stippling of the lower spine and long bones and periosteal cloaking. In contrast to the normal morphology of the epiphyses and growth plates, the marrow was filled with loose fibrous tissue containing numerous large multinucleated osteoclasts which were associated with Howship's lacunae on the endosteal surface. We suggest the term "Pacman dysplasia" to describe this unusual histologic change that characterizes this new bone dysplasia.