Back in the first half or so of the last century people naively clumped
things and thought that one day there would a cure for "cancer"
(singular).

For quite some time since we have known that there are hundreds of so
called "cancers", and those subsets sometimes have their own subsets
and some of those subsets have their own subsets.

So it is with lymphoma, a malignancy of the lymphocytes. There are
multiple types of lymphoma that ferrets can get and of those at least
one has subsets that differ greatly in how aggressive they are.

For people here I will just mention the basic types of lymphoma that
are found in ferrets, but you can look in the FHL and FML archives
for further information.

Any of the types of lymphoma can present symptoms only near the end,
but some give warnings early enough to treat. In fact, even some vets
have lost personal ferrets only to find hidden lymphoma that had
squirreled away in some place where it did not show up on most tests,
for example in the marrow, only to then ravage the animal too rapidly
to do anything. Luckily, for most forms that is not the typical
presentation (though it is very common for Juvenile Lymphoma).

Here is a segment from an article in a past issue of Ferrets Magazine
by Dr Bruce Williams who has given me blanket quoting permission that
I am careful to not abuse:
BEGIN QUOTE
Lymphoma is a common occurrence in ferrets. Overall, it is the third
most common neoplasm overall in ferrets (following insulinoma and
adrenal neoplasms) and the most common of all malignancies. And it
doesn't discriminate based on age - while the majority of cases affect
animals 5 years and older, animals may be affected as young as 4 months
of age.

While a few similarities exist, as outlined below, lymphoma is
unique in its dissimilarity between cases. Every case is unique and
unpredictable -- which organs are affected, how rapidly the diseases
progresses, etc. The tumor may choose to infiltrate critical organs
such as the brain, kidneys, or heart, or non-critical areas such as
the eyes or skin.
END QUOTE

Lymphoma types can look like a range of illnesses or medical problems
(like blockages) in ferrets because they can be present in so many
organ systems, and often in more than one at the same time.

Another quote from Dr. Williams' article:
BEGIN QUOTE
Let's look at the basics of lymphoma. In the ferret, three major forms
of lymphoma exist, which generally differ from each other in terms of
age of animal affected, the organs affected, the average survival time,
and the predicted response, if any, to therapy. END QUOTE

The lymphocytic form (the adult-onset form) is the most common one
in ferrets. When you read about people treating lymphoma in ferrets
this is the one that they usually mean, and often in this form the
peripheral lymph nodes will be enlarged though sometimes deeply
internal nodes are the first to enlarge and you can can not know about
that casually. This is the slowest progressing of the lymphoma types,
but in the archives you will find work on which markers show how
aggressive the subsets of this form will be. Some ferrets with
lymphocytic lymphoma can live about a year and the slow growth means
that there is the chance that treatment will bring remission. All of
us who have had ferrets for any length of time have treated ferrets
with this type of lymphoma.

Lymphoblastic lymphoma is the juvenile form.

Malignancies typically take a decent amount of time to get from the few
cell stage to being a pronounced disease. That is true for a number of
other neoplasias as well. (Many human lung tumors probably first began
growing 30 years before they are pronounced, and some growths in
ferrets appear to typically show up about 3 years after the triggering
event, with work on that regard in things like adrenal neoplasia and
also the third type of lymphoma which will be discussed later.)

Juvenile lymphoma/ Lymphoblastic lymphoma usually appears LONG before
the 3 year mark in age. Most who die of it are under 2 years of age.
Arian was just shy of one year but there have been kits lost at just a
few months of age. To manage that there usually needs to be a genetic
involvement. I have not had time to keep up on work on this regard so
will need to make the time and do so, but genetic problems which could
lead to such difficulties could be genetic variants that promote
mutations, or the lack of active genes that kill off mutated cells well
(useful when working since everyone always has some mutated cells in
them), or epigenetic changes that have a critical gene turned on or
turned off, or perhaps stem cells are involved so the disease is
present even before birth like teratomas are, or...

Again quoting Dr. Williams:
BEGIN QUOTE
In this variant, myriads of immature (blastic) cells infiltrate
visceral organs in large numbers, while the lymph nodes remain
unaffected until the latest stages of disease. Infiltration by
neoplastic cells results in enlargement of major organs and the most
commonly affected organs are the liver, spleen and thymus. In most
cases, thymic enlargement rapidly becomes a life-threatening issue,
as the thymus occupies the thoracic cavity, a space enclosed by the
unforgiving cage of the ribs. As the neoplastic cells expand the thymus
(as seen in Figure 2), the thymus compresses the adjacent lungs, making
it difficult, and eventually impossible, for the animal to breathe. In
juvenile lymphoma, labored breathing is often the first clinical sign
noticed by the owner, and this form's early compromise of pulmonary
function is the reason that it carries the shortest survival time of
all variants (only 2 weeks after diagnosis.)
END QUOTE

Luckily, it is rare disease. In over 30 years with ferrets we have
encountered it twice. Helix got a few weeks after symptoms began and
in her case it got into her spinal cord which was very horrid; Arian
got only a few days because her thoracic growth was filling her chest
cavity with blood, but she actually got to play even on her penultimate
day but then was actively dying on her final day. I know of only one
ferret with JL who somewhat responded to treatment (but died after it
went to the spinal cord) and that ferret was one of the unusual adults
with JL and had it progress more slowly than it usually does.

The immunoblastic-polymorphous variant is the final variant of lymphoma
that is well known in ferrets. This is the form that appears in clumps,
with multiple ferrets in the same home breaking with it at about the
same time. Work at MIT showed that there appears to be a viral trigger
an average of about 3 years before the onset of these cases of
lymphoma. We have been through that twice, too, with the final bout
killing over about a year's time. We are not in the midwest but for
some unknown reason that seems to be where this shows up more.

Yet another quote from Dr. Williams:
BEGIN QUOTE
In fact, in 1995, researchers at the Massachusetts Institute of
Technology were able to transmit lymphoma between ferrets with cell-
free extracts, suggesting a possible viral cause for lymphoma, or at
least some forms of it. The development of lymphoma in this experiment
took several years in inoculated individuals, and not all inoculated
ferrets developed lymphoma, but the results of this study are too
intriguing to ignore. To date, however, a virus has yet to be
identified or isolated from malignant lymphoma in ferrets.
END QUOTE

We have also treated ferrets with that form and possibly managed to
slow it down and to add to quality of life.

So, now you know about the primary forms of lymphoma found in ferrets.
Please, use the two archives to learn more about treatment options for
the types that can be treated.

Arian's death on Monday should help someone. Maybe this information
will allow it to do so.

Sukie (not a vet)

Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.miamiferret.org/
http://www.ferrethealth.msu.edu/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
all ferret topics:
http://listserv.ferretmailinglist.org/archives/ferret-search.html

"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)
On change for its own sake: "You can go really fast if you just jump
off the cliff." (2010, Steve Crandall)

[Posted in FML 7422]