Treat this as an supporting document to Bruce William's excellent post
above taken from FHL digest 348.  I especially liked his providing the
direct translation of "tumor" as "swelling", and his explanation that not
all growths which can metastasize do so readily.
 
These definitions are combined ones from medical, veterinary, and biology
dictionaries, but emphases are mine and i am willing to be corrected if I
blew it...
 
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 [See the notes of Dr. Bruce
Williams above in relation to why LOCAL reoccurance is NOT metastasis.]
 
neoplasm, malignant: a neoplasm with the characteristics of anaplasia,
invasiveness and metastasis
 
There are several other subsets of neoplasia in this dictionary.
 
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.
 
[Originally] [Posted in FML issue 3644]
[Posted in FML issue 3736]
[Posted in FML issue 3770]