http://www.smartgroups.com/message/readmessage.cfm?gid=1423922&messageid=359
 
>I discovered a lump on Phoebe's head in February - it's at the back of
>her head, right next to her right ear...it covers the entire right half
>of her head from the ear back, and extends down her neck.  An xray
>determined that it is attached to her skull, and was itself calcifying,
>turning into bone.  The tumor/mass is inoperable, and was diagnosed as an
>osteoma/osteosarcoma (depending on whether it's malignant or not, but
>it's not being checked).
>
>Based on how much it had grown from February to June, when this other vet
>saw her, we're guessing Phoebe has another 4-8 months before the tumor
>will be causing her too much pain/discomfort.  The vet said it could
>probably double in size (at that time) and not bother her, but once it
>tripled, it would probably be time to put her down.
 
Well, I think based on your description, that we are probably dealing
with a chordoma rather than an osteosarcoma.  I have seen several
chordomas now which arise either on the skull or in the neck vertebrae.
There are some significant differences which may affect the progression
of this case.
 
Chordomas are more infiltrative than osteosarcomas, and are more likely
to infiltrate the spinal cord earlier.  Likely that this will occur in
the area of the cervical vertebrae - the back end of the skull is
probably the farthest from critical structures.
 
Most ferrets develop difficulty walking prior to showing a lot of pain
from this condition.  It is likely that this ferret will lose the ability
to move before it will be necessary to put her down for pain.
 
While chordomas are far more common at the end of the tail, they may
arise anywhere along the spine, and due to their infiltrative nature,
surgical excision in these locations are not very useful.
 
With kindest regards,
Bruce Williams, DVM
[Posted in FML issue 3848]