Magnetic resonance imaging findings of an intradural extramedullary hemangiosarcoma in a dog

: An 11-year-old male Miniature Dachshund was referred for acute neurological deficits in the pelvic limbs. T2-weighted magnetic resonance imaging revealed that the spinal cord at the L1-2 intervertebral disc space was heterogeneously hyperintense in the sagittal plane and was mildly compressed from the ventral side by a small hypointense mass in the transverse plane. However, the lesion showed mass enhancement and severe spinal cord compression on post-contrast T1-weighted imaging. On three-dimensional myelography, a "golf tee sign" was observed around the mass. Therefore, we diagnosed an intradural extramedullary lesion. The mass was surgically removed and histologically diagnosed as a hemangiosarcoma. The "golf tee sign" observed on magnetic resonance myelography may be useful for distinguishing intradural extramedullary masses from intramedullary masses.