While there are some cases of JL (Lymphoblastic form of lymphoma) which
have progressed slowly they are extremely rare and usually in the even
more rare cases where this form of lymphoma appears in an adult ferret.
Days to weeks after symptoms until death is far more common with the
average being two weeks from beginning of symptoms to death according
to a past paper by a highly respected ferret pathology expert. If the
other veterinarians who have reviewed this case as consultants are
not ferret pathology experts you may be fortunate enough to have this
instead be an infection. Remember, too, that there will even be some
ferret experts who have not encountered JL since lymphoblastic lymphoma
is one of the more rare forms of lymphoma. What you described can be
consistent with some types of infections, even more so than with the
usual presentations of JL since this is long time frame, the progress
has been slow, and the thoracic changes mentioned did not include an
enlarged thymus but instead just mention swelling. See if some experts
on ferret pathology such as those at Michigan State agree with the JL
conclusion. I will hope for you that this case with its very unusual
presentation is instead an infection that is responsive to medication.

Another possibility that has to be strongly considered with this
description and timing is heartworm. It is a good fit. That requires
prompt and correct treatment, but even then if left too long it can be
fatal. This remains the best article I know on that extremely serious
illness:

http://www.miamiferret.org/heartworm.htm

Either a serious thoracic infection or heartworm will also be serious
diagnoses that must be eliminated as possibilities and treated
correctly for survival.

This time of year many vets will also want to eliminate the possibility
of allergies from the things which can progress that slowly and cause
inflammation. Allergies can be very serious depending on the level and
type of allergy.

Sukie (not a vet) Ferrets make the world a game.

Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.miamiferret.org/
http://www.ferrethealth.msu.edu/
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)

A nation is as free as the least within it.

[Posted in FML 7817]