Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Six The Spine 697
FIG. 6-45 An 8-year-old male Siberian Husky with a slow
onset of tetraparesis. A, The lateral myelogram revealed
ventral extradural masses centered in the bodies of C4 and
C5 (large white arrows). The spinal cord at C3 appears
enlarged in the dorsoventral aspect due to a lateral
extradural mass (small white arrow). B, The ventrodorsal
view revealed a left lateral extradural mass at C3 (small
white arrow) and ventral extradural masses at C4 and C5,
causing the cord to appear widened at these sites (large
white arrow). Differential diagnoses include any of the multifocal
extradural masses. The most likely is metastasis to
the internal vertebral venous plexus (dorsal venous vertebral
sinuses). Diagnosis: Renal carcinoma metastasis to the
cervical internal vertebral venous plexus.
A
B
chondrosis in the appendicular skeleton. A lesion that resembles osteochondrosis has been
reported in the sacrum, predominantly in German Shepherd dogs. 207 This lesion was identified
in older dogs with cauda equina compression and in younger dogs without cauda
equina compression. A radiolucent defect was identified in the dorsal aspect of the cranial
endplate of S1, along with endplate sclerosis and one or more bone densities that were
identified on the ventral midline of the spinal canal. In older dogs that also had other
degenerative changes, such as spondylosis and degenerative joint disease of the articular
facets, cauda equina compression was documented myelographically. The bone densities
appeared to be attached to the intervertebral disc and were identified histologically as hyaline
cartilage with a bone center. In affected immature dogs, the cartilaginous mass
appeared histologically to be associated with the sacral physis.