The case of a 2 1/2-year-old boy with diffuse cystic angiomatosis of bone is presented. No evidence of visceral involvement was recorded. The clinical, radiographic and histologic findings during the course of the disease process are discussed. At the age of 15 years the patient died of neurologic alterations developed due to massive osteolysis and collapse of the cervical spine, and severe dyspnoea, secondary to persistent bilateral pleural effusions.