"Ears of the lynx" sign on MRI: A radiologic clue to hereditary spastic paraplegia.

Hereditary spastic paraplegia (HSP), also known as Strümpell-Lorrain disease, comprises a heterogeneous group of inherited neurodegenerative disorders characterized by progressive lower-limb spasticity resulting from corticospinal tract degeneration. Clinically, HSP is divided into a pure form, limited to pyramidal tract signs, and a complicated form associated with additional neurological manifestations. We report a familial case involving 2 male siblings born to consanguineous parents who presented with complicated HSP. Brain magnetic resonance imaging demonstrated thinning of the corpus callosum and a characteristic T2/FLAIR cone-shaped hyperintensity at the anterior horns of the lateral ventricles, known as the "ears of the lynx" sign. This radiologic feature is strongly associated with SPG11 and SPG15, 2 common genetic subtypes of complicated HSP. In regions where genetic testing is limited by availability or cost, recognition of this imaging sign may provide an important diagnostic clue and facilitate early identification of hereditary spastic paraplegia.