Imaging diagnosis--Hemorrhagic meningioma.

An 8-year-old Labrador Retriever developed acute central vestibular signs. An extra-axial mass was detected on MR images ventral to the brainstem. The mass was both T1- and T2-hypointense; there was also thin-rimmed patchy contrast enhancement. These findings were nonspecific, but the extreme T2-hypointensity was notable and suggested a hemorrhagic mass. The histologic diagnosis was anaplastic meningioma with acute hemorrhage. These findings document an unusual appearance of a meningioma in MR images due to intratumoral hemorrhage.