DIAGNOSIS: Cervical vertebra (C2-C3): Invasive hemangioma with severe spinal cord compression.
REMARKS: Severe compression of the spinal cord by this invasive hemangioma is the cause of the reported neurologic abnormalities. This tumor was diagnosed as an invasive hemangioma, and not a hemangiosarcoma, based on the lack of cellular pleomorphism and minimal mitotic activity. The slide was additionally reviewed by Dr. Powers, who agreed with the diagnosis.
GROSS FINDINGS: A reportedly one-year-old intact male domestic rat was submitted for necropsy examination. The rat was in fair body condition and contained adequate amounts of subcutaneous and visceral adipose tissue. Tissue autolysis was mild. The mandibular incisors were overgrown. There was a 2 mm in diameter ulceration in the hard palate, just caudal to the maxillary incisors. The right side of the vertebral body of the second /third cervical vertebrae was locally extensively effaced by a poorly demarcated, firm, dark red mass. The mass invaded into the vertebral canal and severely compressed the associated spinal cord. The mass occupied approximately 80% of the vertebral canal. A complete postmortem examination was performed and no significant lesions were observed in the remaining tissues.
HISTOPATHOLOGY:
Slides 1-2.
Cervical spinal cord: Extending from the lateral aspect of the vertebral bodies of C 2/C3 (slide 2) was a poorly demarcated, locally invasive, unencapsulated mass. The mass was composed of multiple, variably sized erythrocyte -filled vascular spaces that were lined by a single layer of relatively well-differentiated endothelial cells and separated by variably thick fibrous septae admixed with trabeculae of woven bone. The endothelial cells contained fusiform nuclei with finely stippled chromatin and 0-1 small basophilic nucleoli. Mitoses were rare, and nuclear variation was minimal. A few of the vascular spaces were multifocally occluded by fibrin thrombi. Islands and trabeculae of reactive woven bone or dense fibrous tissue circumscribed the mass. The mass invaded into the vertebral canal and severely compressed the associated spinal cord. Approximately 60% of the spinal cord white matter was lost. Within the remaining regions of spinal cord, there were multifocal dilated myelin sheaths that were generally devoid of an axon or less frequently contained a spheroid. The cervical spinal cord cranial to the lesion (slide 1) contained scattered dilated myelin sheaths, spheroids, and digestion chambers within all funiculi.
Slide 3.
Thoracolumbar spinal cord: Similar lesions were observed as those described in slide 1, but were more prominent in the ventral and lateral funiculi.
Chad B. Frank, DVM, MS, DACVP
Prelim: 10/07/2015
Full Report: 10/08/2015 ljb
