summary Melorheostosis is a rare benign painful disorder of the extremities characterized by formation of periosteal new bone. Patients typically present in the first 4 decades of life with localized pain and reduced range of motion. Diagnosis is made radiographically with a "dripping candle wax” appearance with dense hyperostosis that flows along the cortex of the bone. Treatment is observation and medical management for those with mild symptoms and normal joint motion. Surgical bone resection and contracture release is indicated for those with severe symptoms and joint contractures. Epidemiology Demographics usually presents before age 40 no sex predilection Anatomic location more common in the lower extremities, but can occur in any bones Etiology Genetics non-hereditary Presentation Symptoms pain reduced range of motion joint contractures Physical exam fibrosis of the skin with significant induration and erythema is common reduced range of motion painful hyperostoses Imaging Radiographs cortical hyperostosis “dripping candle wax” appearance with dense hyperostosis that flows along the cortex of the bone hyperostosis may flow across joints Studies Histology normal haversian systems with enlarged bone trabeculae and without cellular atypia or mitotic figures Treatment Nonoperative symptomatic treatment indications mild symptoms with adequate motion bisphosphonates are shown to help with pain and swelling Operative hyperostotic bone resection with contracture release indications severe contractures, limited mobility, and pain