Melorheostosis, also known as Leri disease, is an uncommon mesenchymal dysplasia manifesting as regions of sclerosing bone with a characteristic dripping wax appearance or flowing candle wax appearance.
Although changes occur in early childhood, age at presentation is often later, and the condition often remains occult until late adolescence or early adulthood. In only approximately half of the cases is the diagnosis made before the age of 20 2.
There is no recognised familial predisposition 3.
The condition, especially in childhood, is usually asymptomatic, being diagnosed as an incidental finding on radiographs obtained for another purpose 1,3. When melorheostosis does manifest clinically, the most common presentation is of joint contracture or pain, which are more common in adults 3.
Melorheostosis can be either monostotic or polyostotic and tends to be monomelic. It has a predilection for long bones of the limbs, although it can be seen almost anywhere. Hands and feet are not infrequently involved whereas involvement of the axial skeleton is rare 1,2. The condition has a tendency to give a sclerotome distribution.
- sclerodermic skin changes: thickening and fibrosis of overlying skin
- hyperpigmentation of overlying skin 4
- muscle atrophy
- vascular tumours and malformations
- other tumours, e.g. osteosarcoma, malignant fibrous histiocytoma 4
Radiographs are considered sufficient for establishing the diagnosis.
Five patterns have been described 1:
- periosteal cortical thickening is characteristic, but endosteal thickening is also seen in many cases, especially when the age of onset is in adolescence, where it may be purely endosteal 5
- thick undulating ridges of bone, reminiscent of molten wax (dripping wax appearance or flowing candle wax appearance)
- confined to sclerotomes, and can be seen apparently flowing across joints to the next bone
- myositis ossificans-like
- osteopathia striata-like
Not infrequently features of melorheostosis, osteopathia striata and osteopoikilosis may co-exist in so-called overlap syndromes. These conditions may share an underlying aetiology (loss of function mutations in the LEMD3 gene) 1.
Usually, the lesions show low signal on all imaging sequences, with no enhancement.
An increase in radiotracer uptake is usually present on late phase bone scans 2.
Treatment and prognosis
The disease is of variable severity, but in general follows a chronic progressive course in adults and a faster course in children, occasionally resulting in substantial disability from contractures or deformity.
Conservative management is often unrewarding, and in severe cases, surgical intervention may be required, including tendon release, osteotomies and even amputation 1-3.
History and etymology
The name is derived from the Greek words for limb (melos) and flow (rhe), due to its characteristic appearance of flowing hyperostosis 1,3.
Possible considerations include
- 1. Bansal A. The dripping candle wax sign. Radiology. 2008;246 (2): 638-40. doi:10.1148/radiol.2462050537 - Pubmed citation
- 2. Motimaya AM, Meyers SP. Melorheostosis involving the cervical and upper thoracic spine: radiographic, CT, and MR imaging findings. AJNR Am J Neuroradiol. 27 (6): 1198-200. AJNR Am J Neuroradiol (full text) - Pubmed citation
- 3. Younge D, Drummond D, Herring J et-al. Melorheostosis in children. Clinical features and natural history. J Bone Joint Surg Br. 1979;61-B (4): 415-8. J Bone Joint Surg Br (link) - Pubmed citation
- 4. Hollick RJ, Black A, Reid D. Melorheostosis and its treatment with intravenous zoledronic acid. BMJ case reports. doi:10.1136/bcr.04.2009.1757 - Pubmed
- 5. Vincent J. Vigorita. Orthopaedic Pathology. ISBN: 9780781796705