A meningioma with hyperintensity on T1-weighted images in a dog.

A male six-year-old Pomeranian showed recurrent seizures and progressive left hemiparesis. MRI revealed a mass in the right paramedian frontal-temporal region with hyperintensity on T1-weighted (T1W) and mixed-intensity on T2-weighted (T2W) images. After gadolinium enhancement, the mass was enhanced homogenously and demonstrated the dural tail sign. Surgical resection of mass was performed and its histological diagnosis was meningioma. The meningioma of this case had a high cellular density with some lipid contents and intra- and extra-tumor hemorrhage, however, calcification was not found. These cellular characteristics may contribute to a higher signal intensity on T1W imaging.