Fact-sheet: Adamantonoma
Updated on 08/13/2020 at 3:56 PM
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Definition
Very rare primary bone tumor occurring almost exclusively in the anterior cortex of the tibial diaphysis.
Involvement of the femur or fibula is rarer.
Other sites of involvement have been described.
Affects young adults.
Clinical features
- Bowing and painless swelling of the anterior aspect of the tibia
- Pathologic fracture
Laboratory findings
- Hypercalcemia may occur
Radiography
At the initial stage: eccentric cortical lesion, unifocal or, more rarely, bifocal (tibia and ipsilateral fibula), small in size, without associated periosteal reaction.
At a more advanced stage: the tumor takes on a “soap bubble” appearance.
Peripheral osteosclerosis is common, and cortical destruction as well as periosteal reaction may be associated
MRI
Indicated to assess tumor extension into the bone marrow and adjacent structures
Two patterns of presentation:
- a lobulated, solitary lesion, occasionally bifocal,
- or multiple small nodules grouped into one or several foci
Nonspecific lesion signal and enhancement, but the location (anterior tibial cortex) is more suggestive
A lesion extending over a greater length (> 10 cm), “moth-eaten” margins, and involvement of the medullary cavity would be more suggestive of adamantonoma
Nuclear medicine
Bone scan:
- Hyperfixing lesion
- Demonstration of multifocal or synchronous involvement of an adjacent bone
Management
En bloc surgical excision with reconstructive surgery (bone graft)
Prolonged clinical and radiologic follow-up
Classification
Pathology: tumor characterized by the presence, in variable proportions, of epithelial cells within an osteofibrous tissue.
2 histologic subtypes:
- osteofibrous dysplasia-like adamantinoma (predominance of the osteofibrous component in a central position)
- classic adamantinoma (predominance of the epithelial component with clustered cells).
Adamantinoma exhibits local aggressiveness and can recur and metastasize to distant sites (lung and bone)
Differential diagnosis
- Osteofibrous dysplasia
- Nonossifying fibroma
- Fibrous dysplasia
