Actually, these are usually rapidly growing tumors, but the bigger problem
is that they are not usually noticed until they they are relatively
advanced - as a result, the average lifespan of affected animals is about
two weeks after diagnosis.  This tumor has been percolating along for a
while, fairly silently, and you didn't get any warning until it had taken
up a significant amount of space in the chest.
 
Unfortunately, there is limited room for anything in the chest but the
lungs and heart, and when the tumor grows, it is usually at the expense
of the lungs' expansion.
 
>He didn't have enlarged lymph nodes, like on the neck or by the legs.
>Also no other organs were involved, just one massive tumour.
 
In juvenile forms, lymph nodes are rarely involved.  Lymph node involvement
is more commonly seen in the type of lymphoma seen in older ferrets.
Looking at the report, there is no mention of examination of other samples.
It may be that the organs didn't appear grossly involved, but were not
sampled.  In my experience, in these cases, spleen and liver are generally
also affected by the neoplastic process.
 
>This is the PM report:
>
>History: Anterior thoracic mass post mortem samples
>
>Diagnosis: Lymphoma (Lymphosarcoma)
>
>Commentary:
>
>These two samples from an anterior thoracic mass are histologically
>similar.  The mass is characterized by dense sheets of uniform,
>intermediately differentiated, lymphoid cells with scant cytoplasm and
>medium-sized nuclei (c.  1.5x RBC diameter).  The mitotic index is very
>high (frequently in excess of 25 per high power field).  The histopathology
>is pathognomonic for malignant lymphoma, probably lymphoblastic.  Since no
>normal tissue remains in the samples I cannot identify the organ in which
>the tumour has originated: mediastinal lymph node or thymus, most likely.
>
>Malignant lymphoma (lymphosarcoma) is the commonest malignancy of the
>domestic ferret.  It most commonly arises spontaneously, although there
>is increasing evidence of a transmissible form.  Several variants of the
>disease exist: a small-cell type is more commonly encountered in older
>animals while the lymphoblastic form is seen more frequently in younger
>(less than 2 years old) ferrets.  This latter form is commonly associated
>with tumours in multiple organs, causing multi-systemic disease.  The
>prognosis is always poor.
 
This is an excellent report - right on the mark.
 
With kindest regards,
Bruce H. Williams, DVM, DACVP
 
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[Posted in FML issue 3418]