Ankle and Foot 47 - Department of Radiology - University of ...

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47 Ankle and Foot 2315 47
Figure 47-121. Intraosseous lipoma discovered as
an incidental finding in a 43-year-old. A, Lateral
radiograph of the right calcaneus shows the lucent
lesion in the anterior half with a well-circumscribed
border (open arrowheads). Centrally, there is a small
sclerotic focus (black arrowhead), characteristic of an
intraosseous lipoma. B, Lateral radiograph of the
contralateral left calcaneus is shown for comparison.
A lipoma, intraosseous or otherwise, should
be isointense to fat on all imaging sequences. C,
Midsagittal T1-weighted image shows the signal
intensity of the lipoma (open arrowheads) to be
isointense to that of the surrounding fatty bone
marrow. The central sclerotic focus (black arrowhead)
is dark on all imaging sequences. D, On the
corresponding T2-weighted fat-suppressed image, the
fat in the lipoma suppresses to a degree similar to that
of the surrounding fatty bone marrow so that it is
nearly inconspicuous.
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Figure 47-122. Chondrosarcoma arising from the
calcaneal tuberosity 30-year-old. A, Lateral
radiograph. This patient complained of heel pain for
10 months until the sclerosis in her calcaneus was
recognized. B, Sagittal T1-weighted image shows
diffusely decreased signal in the calcaneus
corresponding to the radiographic sclerosis. C, Sagittal
fat-suppressed T2-weighted image reveals marrow
edema only at the periphery of the sclerotic region.
There is, however, extensive bright signal in the soft
tissues immediately plantar to the calcaneus,
indicating that the tumor is extending out of the bone
and into the soft tissues. D, Sagittal post–gadolinium
contrast fat-suppressed T1-weighted image
demonstrates enhancement only at the periphery of
the osseous and soft tissue masses. This enhancement
pattern is due to the relative hypovascularity of
chondrosarcomas.
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9/9/2008 5:36:27 PM