MR imaging features of brain stem hypoplasia in familial horizontal gaze palsy and scoliosis

Abstract

We report the case of a child with horizontal gaze palsy, pendular nystagmus, and discrete thoracolumbar scoliosis. MR imaging of the brain depicted pons hypoplasia with an absence of the facial colliculi, hypoplasia, butterfly configuration of the medulla, and the presence of a deep midline pontine cleft (split pons sign). These MR imaging findings suggest familial horizontal gaze palsy with progressive kyphoscoliosis, a rare congenital disorder. To the best of our knowledge, MR imaging findings of only 4 similar cases, with or without progressive idiopathic scoliosis, have been reported. We discuss the pathogenesis substratum of this entity. Early recognition of this rare entity is important if supportive therapeutic measures in progressive scoliosis are to be applied.

Fig 1.

Sagittal T1-weighted image. Hypoplasia of the pons and medulla oblongata. Normal corpus callosum.

Fig 2.

Axial T2-weighted image. Deep midsagittal cleft extends ventrally from the fourth ventricular floor originating the split pons sign.

Fig 3.

Axial T2-weighted image. Hypoplasia of the medulla oblongata with butterfly morphology.

Fig 4.

Axial T2-weighted image. At the level of the pons, the floor of the fourth ventricle is flattened and has a tent shape. Absence of the facial colliculi is notable.