Clinicopathologic Features of Intracranial Central Neurocytomas in 2 Dogs

Background In humans, central neurocytomas are rare and typically benign intracranial tumors found within the lateral ventricles, although extraventricular variants have been reported. Intracranial central neurocytomas have not been previously recognized in domestic animals. Objectives To describe the clinicopathologic features of canine intracranial central neurocytomas. Animals Two dogs with spontaneous intracranial and intraventricular neoplasms. Results Both dogs experienced seizures, rapid neurological deterioration, and death from tumor‐associated complications within 5 days of the onset of clinical signs, and had neoplastic masses within the lateral ventricles. A brain MRI was performed in 1 dog, which revealed a T1‐isointense, heterogeneously T2 and FLAIR hyperintense, and markedly and heterogeneously contrast‐enhancing mass lesions within both lateral ventricles. Histologically, the neoplasms resembled oligodendrogliomas. The diagnosis of central neurocytoma was supported by documenting expression of multiple neuronal markers, including neuron‐specific enolase, synaptophysin, neural‐cell adhesion molecule, and neuronal nuclear antigen within the tumors, and ultrastructural evidence of neuronal differentiation of neoplastic cells. Conclusions and Clinical Importance Central neurocytoma should be a differential diagnosis for dogs with intraventricular brain masses. Morphologic differentiation of central neurocytoma from other intraventricular neoplasms, such as ependymoma or oligdendroglioma, can be difficult, and definitive diagnosis often requires immunohistochemical or ultrastructural confirmation of the neural origin of the neoplasm.