Osteofibrous dysplasia is a rare, benign non-neoplastic condition with no known cause. It is considered a fibrovascular defect. Campanacci described this condition in two leg bones, the

tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...

and

fibula The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...

, and coined the term. This condition should be differentiated from nonossifying fibroma and

fibrous dysplasia of bone Fibrous dysplasia is a very rare nonhereditary genetic disorder where normal bone and marrow is replaced with fibrous tissue, resulting in formation of bone that is weak and prone to expansion. As a result, most complications result from fractu ...

Presentation

The tibia is the most commonly involved bone, accounting for 85% of cases. It is usually painless, although there may be localized pain or fracture, and presents as a localized firm swelling of the tibia in children less than two decades old (median age for males 10, females 13). Several authors have related this non-neoplastic lesion to

adamantinoma Adamantinoma () is a rare bone cancer, making up less than 1% of all bone cancers. It almost always occurs in the bones of the lower leg and involves both epithelial and osteofibrous tissue. The condition was first described by Fischer in 1913. ...

– a tumor involving subcutaneous long bones – stating the common cause to be fibrovascular defect. However, the latter is distinguished from an osteofibrous dysplasia by the presence of soft tissue extension, intramedullary extension, periosteal reaction and presence of hyperchromic epithelial cells under the microscope. Osteofibrous dysplasia may also be mistaken for

, although osteofibrous dysplasia is more likely to show an

immunohistochemical Immunohistochemistry is a form of immunostaining. It involves the process of selectively identifying antigens in cells and tissue, by exploiting the principle of antibodies binding specifically to antigens in biological tissues. Albert Hewett ...

reaction to

osteonectin Osteonectin (ON) also known as secreted protein acidic and rich in cysteine (SPARC) or basement-membrane protein 40 (BM-40) is a protein that in humans is encoded by the ''SPARC'' gene. Osteonectin is a glycoprotein in the bone that binds calci ...

neurofibromin 1 Neurofibromin (NF-1) is a protein that is encoded in humans, in the ''NF1'' gene. ''NF1'' is located on chromosome 17. Neurofibromin, a GTPase-activating protein that negatively regulates RAS/MAPK pathway activity by accelerating the hydrolysis ...

, and

S-100 protein The S100 proteins are a family of low molecular-weight proteins found in vertebrates characterized by two calcium-binding sites that have helix-loop-helix ("EF-hand-type") conformation. At least 21 different S100 proteins are known. They are enc ...

Diagnosis

Treatment

Osteofibrous dysplasia is treated with marginal resection with or without bone grafting, depending on the size of the lesion and the extent of bony involvement. However, due to the high rate of recurrence in skeletally immature individuals, this procedure is usually postponed until skeletal maturity.

References

External links

E-medicine overview
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