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Paper text:
cauda equina syndrome ( ces ) is a complex clinical entity due to compression of lumbosacral spinal nerve roots encompassed in the dural sac .
the fully developed syndrome is characterized by multiple sensory signs and symptoms , including low back pain , saddle hypoesthesia or anesthesia , weakness of the lower extremities and impaired low reflexes , as well as sphincter dysfunction and sexual impotence .
the clinical picture of ces may be asymmetric and can substantially differ in each patient , with various combinations of signs and symptoms , often presenting as partial disease onset .
ces etiology includes compressive causes , either structural or neoplastic , but also non - compressive causes ( ischemic , inflammatory or infectious ) [ 1 , 2 ] . among compressive causes ,
lumbosacral disc prolapse is predominant in frequency compared to spinal neoplasms and spinal stenosis , accounting for 45 , 29 , and 21% of all cases , respectively . despite the wide range of these causative conditions , the majority of them share a common localization at the lumbosacral level .
we present the case of a woman with a clinical picture suggesting ces whose etiology could be assigned to a cervical spinal cord lesion .
a 39-year - old woman presented with a three - day history of paresthesias in the saddle region , posterior thighs , legs and soles , mainly on the left side .
she also complained of sensory loss at the perineal level , but denied urinary retention or urgency .
neurological examination showed only mild hypoesthesia in the perianal and perigenital regions , especially on the left .
lumbosacral magnetic resonance imaging ( mri ) was performed , revealing no lesion at this level ( fig .
the electrophysiological assessment showed delayed conduction of the somatosensorial pathway at somatosensory evoked potentials for stimulus applied to the left leg .
routine laboratory tests , including inflammation indexes , autoimmune and neoplastic laboratory assays , were within the normal range .
cerebrospinal fluid ( csf ) examination revealed a cell count of 13 cells / mm , mainly lymphocytes , while csf total protein content was normal . abundant oligoclonal igg bands and intrathecal igg synthesis were also detected .
serum and csf antibodies to borrelia burgdorferi and treponema pallidum were negative , as were csf culture for bacteria and fungi and pcr assays for an extensive virus panel .
cervical mri showed a t2-hyperintense lesion in the middle - right anterolateral region of the cervical ( c2 ) spinal cord ( fig .
subcortical lesions were also present . this episode was considered a clinically isolated syndrome suggestive of multiple sclerosis , and a high dose of intravenous methylprednisolone was administered .
complete clinical recovery followed , and one month later brain and cervical mri revealed a considerable improvement in cervical mri with size reduction of the previously detected lesion .
one year later no relapses occurred ; no new lesions were detected at neuroimaging during follow - up .
as previously mentioned , all potential organic explanations for a clinical picture suggestive of ces are typically searched for within the lumbosacral portion of the spine , and lumbar spine mri is currently the method of choice to visualize and investigate cauda equina nerve roots within the thecal sac , as suggested by the limited available literature which identified lumbosacral mri scans as gold standard for ces diagnosis [ 3 , 4 , 5 ] . however , in some cases ces patients may have normal lumbosacral mri ( around 50% of cases ) , as well as no other clear organic causes of ces , leading to an assumption of a  functional origin of the clinical findings .
the present observations suggest the possibility to consider a cervicodorsal lesion during diagnostic assessment in cases of ces with normal lumbosacral mri , variability of spinal cord lesion localization being an important point to consider given the somatotopic organization of the spinothalamic sensory fibers ( fig .
indeed , we can not rule out that the lesion found in this particular case is an incidental finding , but the mri improvement detected one month later points to a temporal relation between the symptoms and the cervical lesion , which in our case may actually explain the clinical picture mimicking ces .
moreover , bowel , bladder and sexual dysfuntion , which are part of the fully developed ces , were missing in our case , as expected since the relevant afferent and efferent neural circuits are located at the lumbosacral level of the spine . in conclusion
, we suggest that in cases presenting with ces symptoms and normal lumbosacral mri , a cervicodorsal lesion should be considered during diagnostic assessment .
we describe the case of a 39-year - old woman with signs and symptoms suggesting cauda equina syndrome . 
 lumbosacral magnetic resonance imaging ( mri ) demonstrated no lesion at this level , while cervical mri showed a t2-hyperintense lesion in the middle - right anterolateral region of the cervical spinal cord , which may explain the symptoms by involving the anterior spinothalamic tract . 
 we suggest that in cases with cauda equina syndrome presentation and normal lumbosacral mri , a cervicodorsal lesion should be considered during diagnostic assessment .