Ganglioglioma in the spinal cord of a steer

An 18-mo-old Aberdeen Angus steer was unable to rise without assistance; and, when standing, the steer walked with flexed forelimbs. Due to the poor prognosis, it was euthanized and autopsied. Grossly, the cervical spinal cord was markedly enlarged at C5-C6 by a yellow, soft, well-demarcated nodule that affected ~70% of the parenchyma. Microscopically, the expansive, multinodular, unencapsulated neoplasm affected mostly the white matter and consisted of 2 distinct cell populations. Small, pleomorphic cells with scant cytoplasm predominated; nuclei were positive for oligodendrocyte transcription factor 2 (OLIG2) and cytoplasm was negative for glial fibrillary acidic protein, compatible with oligodendrocytes. A second population of large round cells with abundant cytoplasm had positive cytoplasmic staining for S100 protein and synaptophysin (SYN), compatible with mature neurons. We diagnosed a spinal cord ganglioglioma in this steer based on histologic features and OLIG2 and SYN immunolabelling.