Hypothesis Three: Neoplasia

There could be a possible tumor in pelvic region supported by the absence of 
trauma, and the gradual onset and persistence over a few weeks with no relief from 
Rimadyl.  On palpation, pain in the right rear leg is far worse than the left suggesting 
localization of the tumor at this site.  Also no pain was found in the stifle or hock joints of 
either leg.  The limitation of movement and local pain suggests tumor destruction and 
proliferation of bone and/or a space-occupying lesion causing asymmetry of joint 
involvement.  Being a large breed young dog, she is predisposed to certain pelvic tumors.