Melorheostosis is a rare form of mixed sclerosing bone dysplasia.
The name is derived from the Greek term melos (limb) and rhein (to
flow). In children, it is characterized by dense linear streaks,
mostly in the inner cortex of the affected bones. In adults,
irregular ossification is seen along the outer cortex, mimicking
candle drippings. Patients with melorheostosis may develop
secondary symptoms related to limitation of motion, joint fusion,
or periosteal irritation.1,2
The etiology is obscure but
Murry and McCreide3
suggested that an infection
associated with nerve roots may be responsible for this rare
condition. They found that the disorder most often involves one or
more segmental sclerotomes, areas of a bone innervated from an
individual spinal sensory nerve. This may in part explain the
monomelic and linear track involvement and distribution of
melorheostoses. A well known feature of hyperostotic bone
remodeling is its distinctive appearance, resembling wax melting
and dripping down one side of a candle. Several cases of this sign
have been reported from antiquity; the skeleton of a 50-year-old
Alaskan Eskimo from the fifth century A.D. and a 25- to 30-year-old
female dating back to 4000 to 5000 B.C. from Northern Chile both
showed hyperostotic lesions resembling candle wax.4
Despite this characteristic feature, atypical presentations,
particularly forme fruste lesions, raise uncertainties about the
diagnosis. Forme fruste lesions are considered the mildest
manifestation of this condition, which may only focally involve the
bone (monostotic) and, as such, is difficult to differentiate from
a focus of myositis ossifications or periosteal
Melorheostosis can be found in all age
groups but is most frequently diagnosed in young adults.
Contracture of joints, fibrosis of soft tissue, and changes in the
skin may be present at birth,6
but in these cases
definitive diagnosis generally is delayed until osseous
abnormalities appear. There is no sexual predilection in the
disorder. In 70 to 80% of cases, melorheostosis is monomelic and
affects one or more contiguous bones.7
It is more common
in lower extremities and is usually appendicular. Other possible
sites include the skull, spine, ribs, and pelvic
The disorder usually is asymptomatic in
children; in adults, it presents with osseous complaints, usually
beginning in the second and third decades of life. Occasionally, it
may present with one or more palpable masses. Most of the clinical
signs of the osseous dysplasia are associated with fibrosis, which
is usually the cause for joint stiffness, angular joint deviations,
contractures (mostly flexion), and other orthopedic
Skin pigmentation, scleroderma, and
tuberous sclerosis-like thickening have been
In rare instances, melorheostosis has
been reported in association with tumors such as spinal column
lipomatous osteosarcoma, and soft-tissue lesions such as desmoid
tumor. Routine laboratory studies usually are unremarkable.
Histologically, sclerosis, soft-tissue fibrosis, and periarticular
calcification may be seen, and though these may lead to bony
ankylosis of the involved joint, none of these signs are
pathognomonic of melorheostosis. Differential diagnosis for this
condition includes osteomyelitis, reflex sympathetic dystrophy,
neurofibromatosis, soft-tissue sarcoma, and metastatic lesions.
This patient's plain radiographs are characteristic (figure 1),
showing wavy cortical hyperostosis which extends along the length
of the bone, resembling flowing candle wax. Magnetic resonance
imaging (MRI) (figure 2) features of melorheostosis include
hyperostosis, which appears as uniform hypointensity on all imaging
sequences. The Tc-99m-MDP three-phase bone scintigraphy image
(figure 3) demonstrates moderate to severe increase in tracer in
the early and late images, including soft-tissue and blood pool
stages of scintigraphy. The course of this condition is
unrelenting; however, it does slow considerably in adulthood.
Treatment usually is symptomatic, though surgical measures such as
osteotomies, excision, capsulotomies, or tendon lengthening often
- Putman CE, Ravin CE:Textbook of Diagnostic
Imaging, ed 3, pp 1435-1438. Philadelphia, WB Saunders, 1988.
- Stark DD, Bradley WG:Magnetic Resonance
Imaging, ed 2, pp 2:2152-2156. St. Louis, Mosby-Year Book, Inc.,
- Murry RD, McCreide J:Melorheostosis and
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- Kelley MA, Lytle K: Brief communication: A
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- Spieth ME, Greenspan A, Forrester DM:
Radionuclide imaging in forme fruste of melorheostosis. Clin Nucl
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Melorheostosis in children. Clinical features and natural history.
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- Kessler HB, Recht MP, Dalinka MK: Vascular
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- Cambell CJ, Papademetrious T, Bonfiglio M:
Melorheostosis, a report of the clinical roentgenographic and
pathologic findings in fourteen cases. J Bone Joint Surg Am
- Ippolito V, Mirra JM, Motta C, et al: Case
report 771: Melorheostosis in association with desmoid tumor.
Skeletal Radiol 22(4)284-288, 1993.
- Dissing I, Zafirovski G: Para-articular
ossification associated with melorheostosis Leri. Acta Orthp Scand
- Morris JM, Samilson RL, Corley SC:
Melorheostosis. J Bone Joint Surg Am 45:1191, 1963.
- Perlman MD: Melorheostosis: A case report and
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