Bone Pathology Database

Teaching Version


Text in Italics is general (instructional) information

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2nd image
The x rays show a cystic lesion in the distal tibia with a distinct border. It had already been biopsied by the time these X rays were taken - hence the break in the cortex.
Differential diagnosis
1) Non ossifying fibroma
2) Aneurysmal bone cyst (but non expansile)
3) Giant cell tumour ( goes almost to joint margin)
4) Simple bone cyst ( patient a little old for this)

Classical X ray features of NOF

- look for well marginated radiolucent lesion, w/ a distinct multilocular appearance;
- lesion is usually irregular & is surrounded by reactive rim of bone:
- look for benign cortical thinning, erosion, slight expansion;
- there are 2 subtypes;
(1) Fibrous cortical defect
- more common lesion;
- is small < 0.5 cm radiolucency w/ in cortex w/ sharply defined cortex;
(2) Metaphyseal defect
- lesion commonly develops in metaphysis of distal femur
cases) or the distal tibia & is eccentrically located;
- located within or adjacent to the cortex;
- may be eccentrically located within the medullary cavity;
- cortex may bulge over the lesion, as lack of remodelling;
- may be surrounded by a well defined thin rim of reactive bone;
- no periosteal reaction is seen unless there has been a frx;

Record 63