I too had a similar problem.  After Weeble's (see my webshots photo albums,
he was abandoned by his Mama at less than a week old) second set of
vaccinations, he developed a lump at the shot site, but it took about a week
to develop!  Vet was concerned, but puzzled as he'd not had such
developments before, but in the past month, after switching vaccine brands,
was having a rash of them.  The first few he biopsied, and they turned out
negative, just an inflammatory reaction to the vaccine.  So we kept a close
eye on him: he got 'felt up' by the vet once a week for 4 weeks, and it
seemed to get smaller, so vet said to only call/bring him in if the lump did
anything besides shrink, and to bring him in for his neuter on the scheduled
time - and by the time his neuter came, lump was almost gone, and two weeks
after that, the lump was completely gone - now I can't even tell exactly
where it was!.

<snip>

FWIW, I also found a lump on my cat a few weeks after she had been
vaccinated.  I took her back to the vet and he said it wasn't an unusual
occurrence, but that I should watch it just in case.  It took a few more
weeks, but the lump did disappear and has not reappeared since (I still
check for lumps every so often, just in case).  And as a human, I get
vaccine-related lumps, too :-)!  (I bruise and scar easily.)

From what I read, 1 in 5000 cats are affected--seems like a lot but as a
percentage, it's .0002%.  And, from
http://littlezoo.com/data/vet/Commonly%20Treated%20Malignancies%20of%20the%20Cat.htm
"VAS may develop from 3 months to 3 years after vaccination" so 6 weeks is a
bit early for the sarcoma to have developed (if you believe the site
quoted).  I think you were wise to bring her in to the vet, and you should
keep your eye on the lump, but you don't need to worry for now.  She has a
very good chance of *not* getting a vaccine-related sarcoma.

Good luck, and let us know how she's doing!

rona

YOu did the best thing for her. I think the lump will be OK. The fact that
the needle aspiration came back negative is a good thing.
Gail

I had a foster kitten that reacted to the vaccine too.  After a few weeks it
went away.. cancer can develop with vaccines, but its usually not that fast.

And you took her to the vet.  Good call, and with this, you did the Right
thing.

Here's a question - where is the research that says this is a
*significant* risk?  Odds are that your vet not only felt that this was of
no risk, but that because a rabies shot may be so routine

First and foremost, I'll go on record as saying I hope this gets better.
Second, keep in mind that I'm not anywhere near a doctor of any sort.

Now then, something I learned is that most sub-independent research (IE,
"this is what happened to me") is something to be taken with a grain  -
nay, about a truckload - of salt.   It is always the people who have
something bad happen to them who yell the loudest, and when something goes
right, the only time you'll hear of it is if it's authoritative research
beyond what the news gives you.  (Besides, the news gives you
pseudoscientific results of initial findings - such as that having a beer
would melt your liver, and next year beer would strengthen your heart, or
something equally ridiculous.)

With that said, keep in mind that, as it is in humans, there is a risk
when you do something - ANYTHING - invasive to a feline, from full blown
open heart surgery to something as simple as a vaccination injection,
however minute the risk is.  There are steps to prevent really nasty
things from happening, but every now and again something does happen, and
there are almost always ways to treat this.

In any case, heed your vet's word before you heed what's online - they are
the one who has the training to know where there are problems.

We had a needle

If the biopsy came back negative, like others have said, there's probably
no worry.

Well, kitty has grown fond of you, yesno? =^^=

The storm will ride out.  Prayers and purrs for you and kitty, I'm sure
this isn't painless.

Considering the needle aspiration biopsy was negative, I wouldn't be
overly-worried.  I personally know of one cat who died of a vaccine (FeLV -
cat was indoor/outdoor, so needed the vaccine) site-induced cancerous tumor
on her shoulder a few years ago, when the cat was 7.  It was inoperable,
because of the location.  Now a rear leg is used for FeLV vax, *if* the cat
needs it, so that an amputation can be performed in the unlikely event of a
carcinoma forming as a result of the shot.

So, I agree to keep a watch on it, but to try to relax in the meantime.
Adopting her was, IMO, a wiser thing to do than to leave her to her own
devices outside.  One can't ever second-guess such a situation - the "what
ifs" - the adverse things that *may* happen, Vs. what is -likely- to be the
overall better situation.  And you chose the likely-to-be-better deals:
adopting her & getting her rabies shot taken care of.  Which it may very
well still turn out to be.

Cathy

--
"Staccato signals of constant information..."
("The Boy in the Bubble")  Paul Simon

I too hope the bump is just some kind of allergic reaction to the shot.
In the future, you might want to discuss with your vet the vaccination
guidelines recommended by the AAFP:
http://www.aafponline.org/about_guidlines.htm
Since we keep our cats indoors only, many vaccines are not necessary.
Others don't need to be given every year, only every 3 years. Talk to
your vet about this.

Just went throught the same thing...1 in 10,000 cats are affected by the
vaccine. I wouldnt worry too much now. I freaked out and my vet assured me
he was OK and within 8 weeks it, the lump was gone