Well, the tests came back and no sign of systemic tumors were detected.  Which of course, as they pointed out, doesn't mean they're not small and lurking somewhere.  But having investigated this tumor cell type, there's a strong, strong probability it is localized.  Fast growing, but localized.  Of course, most of the data comes from canine patients.  

The tumor type is "extramedullary plasmocytoma".  

Soooooo... I am going with amputation.  The surgery is scheduled Friday and while I have the option to pick him up Saturday, it will be Sunday morning that I'll bring him home (assuming no complications requiring a lengthier stay).  

Sebastian:  Regarding his sister, CeeCee -- there's no one she can stay with.  Family are at least a few states away, and friends who could be considered would also already have pets of their own -- and she is DEFINITELY not accepting of other animals other than her twin brother. When I first brought these cats into this home here, Rory adapted quickly, but CeeCee spent four days hiding from me.  I finally found out she'd burrowed behind the books in a bookcase and hunkered down there.  There are actually three other cats here, but when I am not at home the twins are already living separately from them.  I can't put up a third zone.  (NO, I didn't want to be the Crazy Cat Lady, but I'd hoped that when I brought in the two "rescues" that were going to be put down the next day if I didn't, they'd all mainstream together eventually.  CeeCee didn't see it that way, which also goes for one of the three original cats in this household.  I did mention a long and unpleasant story about the twins coming here.  I guess first and foremost is that I still wonder why my 'friends', who knew foreclosure was on the horizon, didn't inquire into "no kill" shelters and waiting-list policies.)

Serious thanks about inquiring about the stitches.  I do know my vet only uses those soft blue cones these days.  When Rory had the initial surgery, he did get the cone off once, and while he seemed mildly depressed while it was on, it was effective.  

Rory is indeed a lovely cat.  He's going to be a long-term companion.  And he'll get his own blog.

For those following this thread, Rory did indeed have surgery two days ago.  

After my last post here, I discovered that he'd started biting at the tumor and that there seemed to be another abcess.  I immediately got the collar back on him.  

He did well post-op, I am told.  I am told that during surgery that his body temp and blood pressure dropped down further than what the doctors would have liked, but they were monitoring him and keeping him warm.  

I just picked him up and dropped his sister off for boarding for a few days.  It looks like with the predicted weather that I may well be spending all day with him tomorrow.  

He's not really walking yet.  

More later -- and you can tell Jill he's interested once he recovers!!!