I had a spayed female who developed a swollen vulva at the age of 3 years.
Fortunately there was an vetrinarian student making a final project about
adrenal tomours in connection with spayed females going into heat.  So
they sent out an invitation to Swedish ferret owners with spayed jills
going into heat.  I got a thourough examination of my jill for free (I had
travel expenses though).
 
In the ultra sound examination no signs of adrenal tumor was found.
 
What they did find was small residues from the spaying (part of the egg
canal etc.) that the surgeon had missed.  On those residues there was
tumours building producing hormones putting the jill in heat.
 
Thus it was due to an incomplete spay.  The reason that it took as long as
three years to show, was that the missed part themselves didn't produce
the hormones but the tumours.
 
I havent read the final report from the project but I called the girl
performing it and she told me that there were more ferrets than mine that
they found residues after spaying in, as cause for the swollen vulva.
(The research was conducted within SVA the Swedish Veterinarian Research
Institute)
 
My advice to you is to assertain thet the veterinarian not only look for
changes in the adrenal during the ultrasound, but also tumours in parts
missed during spaying.  I'm told that it sometimes is sufficient with a
microscopic part missed during spaying if that part developes tumours
later on.
 
I'm no veterinarian and the explanations above are based on my memories of
what I was told so don't expect them to be 100% correct.  If I'm way off
line somewhere I hope that some of the veterinarians on the FML will
correct it.
 
Happy ferreting All ! / Jonas
 
----------------------
Jonas Nygards
Robotics / Autonomous Mechanical Systems
University at Linkoping
[Posted in FML issue 1288]