As there have been so many posts on this subject over the last few days, I
thought I might weigh in on the subject.  If you would like to know more
about lymphosarcoma in ferrets, please surf over to
http://vetpath1.afip.mil/ferrets/lsa.html a reprint of an article I wrote
for Modern Ferret on this subject.
 
A note on Juvenile Lymphosarcoma:
 
JL is one of three types of lymphosarcoma which affect ferrets.  Other
people may classify them differently, but I don't believe in splitting them
down any further, as these artificial classifications add nothing to the
treatment or outcome of this disease.  Of the three classifications that I
discern, juvenile lymphosarcoma is one.
 
JL affects ferrets less than 14 months of age.  I generally refer to this as
the "lymphoblastic" type based on the appearance of the very immature
lymphocytes which characterize this neoplasm.  (Lymphocytes are a type of
white blood cell which are the backbone f th immune response in humans and
animals.) It differs from most cases of lymphosarcoma, which we see in
animals over 4.5 years of age, not only in the maturity of the cells, but in
many other features.  In JL, the lymph nodes rarely get enlarged; the
neoplastic cells accumulate in the organs of the body.  In LL (lymphocytic
leukemia), the neoplasm generally starts in the lymph nodes, causing
enlarged lymph nodes all over the body.
 
JLoften causes neoplasms in many organs of the body at once.  The most
common sites are the thymus, spleen and liver.  The accumulation of massive
numbers of neoplastic lymphocytes cause equally massive enlargement of these
organs from 2-10X their normal size.
 
However, as the thymus resides in the thoracic cavity, while the spleen and
liver reside inthe abdomen, most animals with JL die as a result of thymic
enlargement.  As the thymus enlarges with the addition of the neoplastic
lymphocytes, it compresses the lungs, resulting in fluid accumulation in the
chest, difficulty breathing, and eventual death.  I can certainly understand
why many of these cases are misdiagnosed as cardiomyopathy - the signs of
both are quite similar and both result in a profound accumulation of fluid
in the chest.  If the chest is full of fluid, then all of the normal
structures of the thorax - the thymus, lungs, and heart, will all be hidden
by the fluid on chest Xrays.
 
My advice to vets and ferret breeders - don't automatically assume that the
difficulty that your less-than-2-year-old ferret is showing is due to heart
trouble.  ALWAYS keep lymphosarcoma in your differential diagnosis for any
severe disease of young ferrets.
 
BTW - JL is not the province of ferrets alone.  We see forms of JL in a
number of species, with cattle being the most renowned for deaths due to
lymphosarcoma in animals less than a year of age.
 
Bruce Williams, DVM, DACVP              Chief Pathologist, AccuPath
Dept. of Veterinary Pathology               [log in to unmask]
Armed Forces Institute of Pathology
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[Posted in FML issue 1697]