These definitions of words commonly misused here -- which scare the
begeebers out of folks who don't know their actual meanings -- are
combined ones from medical, veterinary, and biology dictionaries, but
emphases are mine -- suited to common misunderstandings in ferret lists.
 
If you follow the directions in the FML header you will be able to search
in the archives on "FHL" or on "golden oldie" till you find a post that
vet Bruce Williams wrote than explains why a very large number of the
things non-vets call "cancer" are not cancer ( most adrenal growths,
insulinomae ), why a growth type reappearing in the same tissue is not
metastasis, etc.  If you search both very recently and much further back
in Bruce Williams posts in the FML archives you will find ones about why
vets who are not used to ferrets assume that mast cell tumors must be
bad news in them just as they too often are in dogs when actually it's
typically the opposite for ferrets -- with (at that point for the old
post) only one mast cell tumor ever known from a ferret that was malignant
rather than benign.  (I do not know if any further ones have been
confirmed by pathology since then, but do know that vets who don't know
ferrets still regularly just assume they are dangerous instead of learning
more.)
 
Important Note: some more recent dictionaries don't even include the term
"cancer", and I have heard vets who won't use it due to the widespread
confusion out there, and even some vets who won't use "tumor" due to too
many assuming that any tumor is malignant.
 
Tumor: ANY abnormal mass resulting from the excessive multiplication of
cells; a swelling, especially that resulting from the growth of new
tissue; a neoplasm
 
cancer: Any MALIGNANT TUMOR; carcinoma; a carcinoma or sarcoma
 
malignant: pertaining to or denoting progressive growth of CERTAIN TUMORS
which if not checked by treatment SPREAD TO *DISTANT* SITES, terminating
in death; a tendency to progress in virulence, cancer is the best known
example
 
benign: not malignant, as in CERTAIN TUMORS; not recurrent, favorable for
recovery
 
neoplasm: a tumor; any new growth, specifically one in which cell
multiplication is uncontrolled and progressive, neoplasms may be benign
or malignant
 
(Subsets from Saunders:
 
neoplasm, benign: a neoplasm having none of the characteristics of a
malignant neoplasm (see below), i.e.it grows SLOWLY, expands WITHOUT
METASTASIS, and USUALLY does not reoccur, though some types may reoccur
in the same tissue
 
neoplasm, malignant: a neoplasm with the characteristics of anaplasia,
invasiveness and metastasis
 
There are several other subsets of neoplasia in this dictionary but which
I will not include here.
 
metastasis: the transfer or disease from one organ or part to another NOT
DIRECTLY CONNECTED WITH IT
 
anaplasia: loss of differentiation of cells
 
Those who have the _Saunder's Comprehensive Veterinary Dictionary_ will
find that this resource often provides details beyond these bare-bones
descriptions, (though certainly there also will be nuances in practise
that those of us who are not medical professionals simply won't
understand).  It is a marvelous resource; I love it.  If I had a rating
for refs around here it would be among the best buys.  It's better than
any of my other medical dictionaries, even for sorting through things too
technical for me in the _PDR_ books on herbs and on supplements that i
have at home.  Marvelous book: clearly written and very inclusive; more
than worth what it cost.  http://www.wbsaunders.com
[Posted in FML issue 3694]