From:
Bruce Williams, DVM
Date: 2001-11-07 08:58:00 UTC
Subject: Re: Final Report- Sarcoma; Malignant Fibrous Histiocytoma
--- In Ferret-Health-list@y..., elnrrgby1@a... wrote:
> I just got a copy of the final pathology report this evening and
figured I
> would post the results for anyone interested.
>
> Dr. Williams- I sent the remaining tissue samples off today, so
you should
> have them in a few days. Thank you again for helping!!
>
>
> Description/Intreptation:
> 30020
>
> The submitted sections of ferret (Mustela putoris furo) spleen are
of
> excellent diagnostic quality. These contain the primary alteration
of
> sarcoma. The splenic parenchyma is replaced and distorted by
multiple
> proliferative, infiltrative, poorly demarcated, densely cellular,
> non-encapsulated malignant neoplastic masses. The neoplastic cells
are
> arranged in sheets and ill-defined bundles and cords. These consist
of round
> to spindle to large bizarre cells. The round individualized cells
have low to
> moderate amounts of eosinophilic cytoplasm and round to oval to
clefted
> coarsely stippled nuclei. At times these cells exhibit bi- and
> multi-nucleation. These cells are similar to histiocytic cells and
at times
> are also similar to lymphoid cells. The spindle cells are not as
prominent as
> the individualized cells or the large bizarre cells. These have
mild to
> moderate amounts of eosinophilic cytoplasm. The large bizarre
cells have
> abundant eosinophilic cytoplasm with rarely seen eosinophilic
perinuclear
> inclusions. Nuclei are very large, single to multiple, variably-
shaped and
> bizarre with coarsely stippled to vesicular chromatin and
indistinct to
> prominent large nuclei. The degree of anisokaryosis and
anisocytosis is
> marked. The mitotic rate appears low. Other areas of the spleen
exhibit
> extramedullary hematopoiesis and lymphoid hyperplasia. Multifocal
areas of
> hemorrhage with hemosiderin laden macrophages are noted. There are
> multifocal small areas of extracellular eosinophilic material
deposition.
> This material may be fibrin of amyloid. No etiologic agents are
seen.
>
> Spleen: Sarcoma, most consistent with malignant fibrous
histiocytoma (giant
> cell variant) with extramedullary hematopoiesis, hemorrhage and
possible
> minimal amyloid deposition.
>
> Comment: The morphology of this neoplasm is remarkable. The
predominance of
> the individualized round cells, the spindle-shaped cell and the
giant cells
> varies depending on the area of the spleen. In a few areas the
> individualized cells would be hard to differentiate from lymphoid
cells.
> Overall the morphology is most consistent with malignant fibrous
> histiocytoma (giant cell variant). Prognosis is poor. The
presence of the
> possible amyloid is likely of no clinical significance and is
likely
> secondary to the main pathologic process.
Well, malignant fibrous histiocytoma has not been previously seen in
ferrets (if that is what it is.) MFH is a dog diagnosis, and
pathologists should be very careful in makign this type fo diagnosis
without appropriate workup across species line. In fact, MFH is
somewhat of a garbage-can diagnosis with very poorly defined criteria
in the dog, and many neoplasms are often dumped into this category in
lieu of pursuing more definitive diagnoses. Before making a
diagnosis of this nature, I would generally run a battery of
immunohistochemical tests to ensure the diagnosis and rule out the
possibility of lymphoma and several other possibilities, which was
not performed in this case.
I look forward to receiving this interesting case.
With kindest regards,
Bruce Williams, DVM