Diffuse spinal leptomeningeal gliomatosis secondary to a high-grade intraparenchymal oligodendroglioma in a French bulldog

ABSTRACT: Gliomas are among the most important nervous system neoplasia in dogs. Leptomeningeal gliomatosis is a rare condition in which neoplastic glial cells are disseminated to the arachnoid space. We reported a case of an 11-year-old female French bulldog with progressive hindlimb proprioceptive deficit, paraparesis, and paraplegia due to a diffuse spinal leptomeningeal gliomatosis secondary to a high-grade intraparenchymal glioma. Gross examination revealed an expansion of the subdural space by a gelatinous gray circumferential mass in all spinal cord segments and a focal, light brown area in the spinal cord parenchyma. Microscopically, there was a neoplastic proliferation of glial cells in the hippocampus, spinal cord, and subarachnoid space. Neoplastic glial cells were immunopositive for OLIG2, confirming the oligodendroglial origin. Spinal leptomeningeal gliomatosis should be a differential diagnosis for chronic myelopathic signs.