|
Last
examination
Osteosarcoma cancer in her pelvis
05-10-2009
Histopathologic
examination
Submitted are seven, 2 - 3 mm length
True Cut biopsy specimens.
Decalcification and additional
fixation was required.
HISTOLOGY:
Within these pieces of spongious
bone there is infiltration of the
intertrabecular space by sheets of
blastoid oval to polygonal cells
with oval nuclei, moderately
stippled chromatin, usually one
nucleolus and moderate amphophilic
cytoplasm. Intercellular occasional
osteoid-like matrix deposition.
Moderate cell pleomorphism with up
to approx. 4 mitoses / 400 x hpf.
There is multifocal osteolysis with
osteoclast resorption.
MARGINS: Not applicable.
DIAGNOSIS:
Bone: Intraosseous osteosarcoma,
osteoblastic.
BEHAVIOR: Malignant.
PROGNOSIS: Guarded.
COMMENT:
Osteosarcoma (OSA) is the most
common primary skeletal tumor in the
dog. It is typically seen in middle
to older aged dogs, but occasionally
is seen in younger dogs as well.
Seventy-five percent of
osteosarcomas arise in the
appendicular skeleton, often
occurring in the metaphyseal region
of long bones. Of the 25% of OSAs
that occur in the axial skeleton,
those occurring in the mandibular/maxillary
region exhibit a significantly less
aggressive biologic behavior.¶ ¶Histopathologic
assessment of canine osteosarcoma
can reveal many different tissue
patterns and degrees/types of matrix
production (although osteoid matrix
production is required to make the
histologic diagnosis of osteosarcoma).
At this point in time, no definitive
correlation between different
histologic subtypes, degree of
matrix production, degree of
differentiation (i.e.-histologic
grade), and
subsequent biologic behavior has
been generally accepted, although
these studies continue to be pursued
and evaluated. The only histologic
variant of osteosarcoma that has
been shown to have a less aggressive
biologic course, is the parosteal
osteosarcoma. This variant typically
arises from the periosteal surface
of the bone, and has characteristic
radiographic and
histologic features that allow its
differentiation from other more
aggressive forms. Treatment of
canine osteosarcoma typically
requires surgical removal of the
affected limb(amputation) or
affected portion of the limb/bone(limb-sparing
procedure), followed by some form of
adjunctive therapy. Many
chemotherapeutic protocols, some
including immunomodulatory agents,
have been clinically tested and may
provide some degree of increased
disease free interval. Radiation
therapy is usually reserved for
palliation, but more recently has
been utilized pre-operatively to
enhance the initial surgical
procedure. (References: Small Animal
Clinical Oncology, 3rd Ed, pp
378-417, 2001; Textbook of
Veterinary Internal Medicine, 5th
Ed., pp. 535-450, 2000; Proc Vet
cancer Soc 19th Annu Mtg 1999, p.
35.)
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RTG z VIII
2008
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RTG z IX 2009
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