
19 y.o. man with known problem, referred to Orthopedic Clinic for further management.
Multiple hard nodular masses near extremity joints. They are somewhat deep to soft tissues and are non-tender.
Hereditary Multiple Exostoses
Multiple well-defined pedunculated exophytic lesions project from the metaphyseal region of the distal femur and proximal tibia, oriented away from the left knee joint. There is medullary continuity with the bone of origin. The epiphyses and joints are uninvolved.
Well-defined osseus excrescence of the right fibular head which has medullary continuity with the fibula, and very little if any osteoid matrix. The lesion wraps around the tibia posteriorly, and causes deformity of the tibia but no invasion/destruction. Similar lesions are found in the distal tibae bilaterally, causing deformity of the adjacent fibulae.
Multiple well-defined pedunculated exophytic lesions project from the metaphyseal region of the distal femur and proximal tibia, oriented away from the left knee joint. There is medullary continuity with the bone of origin. The epiphyses and joints are uninvolved.
Well-defined osseous excrescence of the right fibular head which has medullary continuity with the fibula, and very little if any osteoid matrix. The lesion wraps around the tibia posteriorly, and causes deformity of the tibia but no invasion/destruction. Similar lesions are found in the distal tibiae bilaterally, causing deformity of the adjacent fibulae.
These imaging findings are diagnostic for Multiple Hereditary Exostoses. For less clear-cut cases, or when only a single lesion is identified, see the TF topic discussion for other diagnostic considerations.
Additional information to supplement the Topic Discussion:
* Though HME is rare in the general population, the prevalence is much higher in two isolated ethnic communities; The Chamorros of Guam (1/1000), and the Pauingassi of Manitoba Canada (1/100).
* HME should be differentiated from Dysplasia Epiphysealis Hemimelica, which also consists of multiple exostoses, but involves the epiphysis, often destroying the joint. It is usually unilateral.
* Multiple exostoses of the tibiae are also associated with Turner's Syndrome, and Fetal Alcohol Syndrome.
* Surgical treatment is on a symptomatic basis, and is usually delayed until after skeletal maturity, unless malignant degeneration occurs.
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