Malignant spinal meningioma in a CD-1 mouse

Area of Science:

• Veterinary Pathology
• Oncology
• Neuroscience

Background:

• Spontaneous meningiomas are uncommon in laboratory animals, with exceptions in specific rat strains and B6C3F1 mice.
• Meningiomas are tumors arising from the meninges, the membranes surrounding the brain and spinal cord.

Observation:

• A male CD-1 mouse presented with severe apathy and hindleg paresis.
• Necropsy revealed no macroscopic lesions, but microscopic examination identified a 3mm malignant meningioma in the distal spinal cord.

Findings:

• The tumor invaded the vertebral canal, nerve roots, and dorsal root ganglia.
• Histopathology showed a highly cellular neoplasm with epithelioid and sarcomatous areas, moderate mitotic activity, and vimentin immunoreactivity.
• Immunohistochemistry was negative for PAS, reticulin, chromogranin A, GFAP, cytokeratin, and S-100 protein.

Implications:

• This case expands the understanding of spontaneous meningioma occurrence in CD-1 mice.
• The findings contribute to the differential diagnosis of spinal cord tumors in laboratory rodents.
• Detailed histopathological and immunohistochemical characterization is crucial for accurate diagnosis of rare neoplasms.