European Journal of Radiology Extra 65 (2008) 37–41 Posterior column atrophy in autosomal recessive hereditary spastic paraplegia: MRI findings Roula Hourani a , Wissam Barada b,* , Taghrid El Hajj b , Mukbil Hourani a , Bassem Yamout b a Department of Radiology, Faculty of Medicine, American University of Beirut Medical Center, Beirut, Lebanon b Department of Internal Medicine, Division of Neurology, Faculty of Medicine, American University of Beirut Medical Center, Beirut, Lebanon Received 7 June 2007; received in revised form 7 October 2007; accepted 29 November 2007 Abstract Hereditary spastic paraplegia (HSP) is a heterogeneous group of hereditary disorders first described by Str¨ umpell in 1880 characterized by degeneration of the corticospinal tracts and posterior columns of the spinal cord. In spite of the advances in our clinical and genetic understanding of HSP’s, the radiological correlates of the disease were never defined. Most of the studies reporting MRI findings, describe non-specific brain abnormalities and spinal cord atrophy. We report two identical twins sisters with the diagnosis of HSP in whom MRI of the spinal cord revealed posterior displacement of the central ependymal canal suggestive of posterior column atrophy. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Hereditary spastic paraplegia; Posterior column degeneration; Magnetic resonance imaging 1. Introduction Hereditary spastic paraplegia (HSP) is a heterogeneous group of hereditary disorders first described by Str¨ umpell in 1880 characterized by degeneration of the corticospinal tracts and posterior columns of the spinal cord. They are usually divided into two groups: a “pure” form and a “complicated” form, comprising in addition to spastic para- plegia, cerebellar symptoms, amyotrophy of the upper limbs, extrapyramidal signs, ophthalmoplegia, optic neuropathy, reti- nal pigmentary changes, skin disorders, mental retardation and peripheral neuropathy. Dominant, recessive and X-linked pat- terns of inheritance have been described. Around 70% of cases follow a dominant mode of inheritance, and 20% show recessive pattern [1,2]. Most of the studies reporting MRI findings of HSP, describe non-specific brain abnormalities such mild to moderate atro- phy of intracranial structures, particularly the corpus callosum, non-specific white matter lesions in the cerebral hemispheres, * Corresponding author at: Wissam Barada, American University of Beirut. P.O. box: 113-6044. Beirut, Lebanon. Fax: +961 1 370802. E-mail address: wb13@aub.edu.lb (W. Barada). abnormal T2 high signal intensity in the posterior limb of the internal capsules and atrophy of the spinal cord [3–10]. We report two identical twins sisters with the diagnosis of HSP in whom MRI of the brain was normal, however, MRI of the spinal cord revealed posterior displacement of the central ependymal canal suggestive of posterior column atrophy. 2. Case report Nineteen-year-old twins’ product of a consanguineous mar- riage born via c-section without any perinatal complications. Both were noticed to have weakness and spasticity in both lower extremities at the age of 3 years. Both had a normal cognitive function, normal speech, normal vision and no difficulty at school. Their neurologic evalua- tion revealed an upper motor neuron disease predominantly in the lower extremities with weakness, spasticity, hyper-reflexia, and an extensor plantar response. Their sensory exam revealed absent vibratory sensation at toes, ankles, and knees; moderately decreased vibratory sensation at hips, and a mildly decreased at fingers. The pin prick and light touch sensation were conserved as was the motor power of the distal upper extremities. Neurography and electromyography revealed the presence of an axonal motor neuropathy or neuronopathy. Their retinal 1571-4675/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2007.11.009