A High Grade Astrocytoma with Pilocytic Morphology in a 5-Month-Old American Bulldog

SIMPLE SUMMARY: Dogs are valuable models for spontaneous intracranial neoplasia in humans. The most common intracranial neoplasm in dogs is meningioma, followed by glioma and choroid plexus tumors. Pilocytic astrocytoma (PA) is a form of glioma and is a common childhood and adolescent tumor in humans. There have been two previous reports of PA in dogs. These cases were both adult dogs and the clinical and imaging features were not described. This report describes a 23-week-old female intact American Bulldog with a 2-week progressive history of neurologic dysfunction. Magnetic resonance imaging (MRI) revealed a large hemorrhagic mass that was confirmed on post-mortem examination to be a high-grade astrocytoma with pilocytic morphology. This case is the first to report a high-grade astrocytoma with pilocytic morphology in a juvenile dog. ABSTRACT: A 23-week-old female intact American Bulldog was presented for a two-week history of progressive circling to the right, twitching, and altered mentation. Magnetic resonance imaging (MRI) revealed a non-contrast enhancing hemorrhagic mass centered in the right thalamus with concurrent subdural and intraventricular hemorrhage. Post-mortem histologic examination of the brain confirmed a mass centered on the thalamus with histomorphologic features consistent with a high-grade astrocytoma with pilocytic morphology. To the authors’ knowledge, the present case is the first to report clinical and imaging characteristics of a high-grade astrocytoma with pilocytic morphology in a young dog.