Digger5 year old male neutered

domestic ferret

Case #: N07-648 Presenter: Travis Heskett, DVM

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History

• Presented to referring veterinarian for depression and hind limb weakness– Referring veterinarian had initially been

concerned about insulinoma– Bloodwork WNL– Mass palpated at the base of the skull – Radiographs showed large osteoproliferative

cervical vertebral lesion

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CT

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Additional diagnostics

• Aspirate cytology– Malignant cells of

epithelial origin

• Neurology consult– Grave prognosis

• Euthanasia

1000x

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Gross Findings--Dorsal

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Gross Findings--Ventral

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Histology

• Infiltration of the neoplasm into musculature overlying skull and into the skull

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Histology

• Neoplasm infiltrating vertebral column with isolated neoplastic nodules within spinal canal

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Histology

• Production of new cartilage and bone by the neoplasm and invasion and remodeling of existing bone

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Immunohistochemistry

Cytokeratin Vimentin

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CNS Compression

• Myelencephalon with moderate to marked axonal degeneration

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CNS Compression

• Compression of the spinal cord with moderate axonal degeneration

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Final Anatomic Diagnosis

• Chordoma—caudodorsal skull in occipital and atlanto-occipital region with invasion into the calavarium, C1&C2, resulting in:– Compression of cerebellum, brainstem, and cervical

spinal cord with moderate to marked axonal degeneration and minimal neuronal degeneration

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Ferret Chordomas

• 3-6 years of age

• Typically occur at the tip of the tail beyond the last vertebral segment

• Do not appear attached to preexisting bone

• Slow growing, do not metastasize

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AFIP website

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Microscopic Appearance

• Classic appearance is that of physaliferous cells surrounding cartilage with a central core of bone

• Immunoreactive to both cytokeratin and vimentin

• The origin of the bone and cartilage is controversial, but may arise from notocord differentiation within the neoplasm

AFIP website

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Chordomas

• Arise from the remnants of the fetal notocord

• Anywhere along the axial skeleton

• Chordomas have also been reported in cervical and thoracic vertebrae of ferrets

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Chordomas in other species

• Also been reported in rats, mink, dogs, cats, and humans• In humans, they comprise approximately 1-4% of

malignant osseous tumors.• In humans, 50% are present in the sacrococcygeal

region, 25% in the sphenooccipital region, with the remainder arising in the vertebral axis.

• Slow growing and locally invasive• 30% metastasize

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Special thanks to:

Dr. Lisa Farina, pathologistDr. David Taylor, advisorHistology service at UF CVMFellow residents

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