Fact-sheet: Osteoma
Updated on 03/17/2016 at 8:28 AM
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Definition
-Rare benign lesion composed of compact cortical bone.
-Unlike osteochondroma, it has no peripheral cartilaginous cap.
-Develops on the surface of a bone, most often in the skull, sinuses (particularly frontal), and mandible, more rarely in the pelvis, clavicle, and long bones.
-Occurs at any age, most often an incidental finding in adulthood.
Clinical features
Asymptomatic unless large enough to impair sinus drainage or compress adjacent structures
Radiography
Very dense, homogeneous, well-defined lesion
CT
Very dense, homogeneous, well-defined lesion.
Almost always develops from the outer table of the skull vault.
May bulge the wall of a sinus.
MRI
Not necessary in typical forms (osteoma hypointense on all sequences, without enhancement)
Nuclear medicine
Uptake on bone scintigraphy
Management
No follow-up required, as there is no significant increase in size once discovered
Differential diagnosis
-Parosteal osteosarcoma: less homogeneous, less dense than parosteal osteoma.
Biopsy if there is any doubt
-Osteochondroma
-Myositis ossificans
-Melorheostosis
-Benign bone island