intramedullary cavernomas ( imc ) are rare lesions especially in children , in whom they represent 1% of all intramedullary lesions . as such , less than 20 symptomatic cases have been reported in the english literature [ 1 , 2 , 6 , 9 , 10 , 16 , 1820 , 2325 ] and predominantly in boys ( table  1 ) . these invariably presented with an acute , severe neurological deficit followed by rapid deterioration due to hematomyelia . confronted with such a dramatically affected patient , the attending neurosurgeon , due to the rarity of the condition , finds no guidelines in the literature and has to decide if and when to operate on a case - by - case basis , based on the child s clinical presentation , magnetic resonance ( mr ) findings , and his or her personal preference . table  1clinical characteristics of children with intramedullary cavernoma in the literatureauthorsgenderage ( years)imc anatomical levelimc multiple levelsodom et al . f12t11nopresent studyf7c5nof10t9t10noc cervical , f female , imc intramedullary cavernoma , m male , t thoracic clinical characteristics of children with intramedullary cavernoma in the literature c cervical , f female , imc intramedullary cavernoma , m male , t thoracic we report two girls presenting with hematomyelia ( one cervical , one thoracic ) and an acute , severe neurological deficit . we present their clinical and radiological details as well as our surgical strategy and outcome . finally , as one of the girls turned out to have a familial autosomal cavernous malformation syndrome , we review the pertinent literature as well . a 10-year - old girl complaining about dorsalgia for several days suddenly developed lower body dysesthesias and a paraparesis . an l1 sensory - motor level , lower limb hyperreflexia including babinski s signs , and decreased rectal sphincter tone were noted . emergency mr demonstrated hematomyelia ( t8t11 ) , intramedullary edema ( t6l1 ) , and an imc at t9t10 ( fig . within 2  h after admission , paraparesis progressed to paraplegia , and therefore , the girl was operated immediately . 1a1a3 preoperative sagittal t1 , t2 , and t2 ffe ( fast field echo ) mr images revealing a markedly swollen cord , including intramedullary edema ( t6l1 ) , hematomyelia ( t8t11 ) , and an imc at t9t10 ; b1b3 3  months postoperative sagittal t1 , t2 , and axial t2 mr images confirming complete resection ; c1c3 2  years postoperative sagittal t1 , t2 , and axial t2 mr images demonstrating a thin spinal cord without evidence of local recurrence ; d1 , d2 2  years postoperative anteroposterior and lateral spinal x - rays to monitor kyphoscoliosis a1a3 preoperative sagittal t1 , t2 , and t2 ffe ( fast field echo ) mr images revealing a markedly swollen cord , including intramedullary edema ( t6l1 ) , hematomyelia ( t8t11 ) , and an imc at t9t10 ; b1b3 3  months postoperative sagittal t1 , t2 , and axial t2 mr images confirming complete resection ; c1c3 2  years postoperative sagittal t1 , t2 , and axial t2 mr images demonstrating a thin spinal cord without evidence of local recurrence ; d1 , d2 2  years postoperative anteroposterior and lateral spinal x - rays to monitor kyphoscoliosis we had no time to localize the lesion preoperatively . consequently , we removed three thoracic laminae and two more after durotomy revealing insufficient exposure of the lesion , which appeared as a dark blue clot shining through the pia mater . after midline myelotomy , the hematoma presented itself , and the cavernoma was gently mobilized and resected . the girl slowly recovered , regaining minimal voluntary movement after 10  days , continence after 9  months , and independent ambulation after 12  months . 1b ) , whereas 2  years postoperative mr shows a thin spinal cord without evidence of local recurrence ( fig . one day after a fall during skating , a 7-year - old girl suddenly developed cervicalgia and severe paresis of her left arm and leg ( grades 12 out of 5 according to the american spinal injury association ) . her paresis improved to a grade 4 , and at 3  months , her residual deficit was minimal . 2a1a3 preoperative sagittal t1 , t2 , and axial t2 mr images revealing a markedly swollen cord , including hematomyelia at c4c6 and a left anterolateral imc at c5 ; b1 , b2 3  months postoperative sagittal t2 and axial t2 ffe ( fast field echo ) mr images , note multiple small cerebral cavernomas ; c1 , c2 2.5  years postoperative sagittal and axial t2 mr images , the cord still appears swollen ; d1 , d2 3.5  years postoperative sagittal and axial t2 mr images , the cord now appears less swollen and the child is asymptomatic a1a3 preoperative sagittal t1 , t2 , and axial t2 mr images revealing a markedly swollen cord , including hematomyelia at c4c6 and a left anterolateral imc at c5 ; b1 , b2 3  months postoperative sagittal t2 and axial t2 ffe ( fast field echo ) mr images , note multiple small cerebral cavernomas ; c1 , c2 2.5  years postoperative sagittal and axial t2 mr images , the cord still appears swollen ; d1 , d2 3.5  years postoperative sagittal and axial t2 mr images , the cord now appears less swollen and the child is asymptomatic at that time , she was operated using a c3c7 laminoplastic technique and motor evoked potential monitoring . the cord at c4c5 was clearly swollen , and the exact position of the cavernoma was determined using ultrasonography ( fig . subtle subpial yellow - blue discoloration was apparent after sectioning the left c4c5 denticulate ligament and gently rotating the spinal cord to the right ( fig . after lateral myelotomy , the hematoma presented itself ; however , mobilizing and resecting the cavernoma was difficult due to a rather limited lateromedial view inside the spinal cord . 3a macroscopic intraoperative image at c4c5 ( left dorsolateral view , one denticulate ligament sectioned ) showing subtle subpial yellow - blue discoloration at the lateral surface of the spinal cord . b ultrasonic intraoperative image at c3c6 ( sagittal view ) specifying the exact location of the cavernoma in the swollen cord segment a macroscopic intraoperative image at c4c5 ( left dorsolateral view , one denticulate ligament sectioned ) showing subtle subpial yellow - blue discoloration at the lateral surface of the spinal cord . b ultrasonic intraoperative image at c3c6 ( sagittal view ) specifying the exact location of the cavernoma in the swollen cord segment the girl did well after the operation showing no new neurological deficits . multiple small cerebral cavernomas and a familial autosomal cavernous malformation syndrome were diagnosed with mutation of the mgc4607/malcavernin / ccm2-gen ( fig . the following 1.5  years , she complained of intermittent cervicalgia and left brachial dysesthesias , with mr suggesting active residual cavernoma ( fig .  2c ) . mr after 3.5  years shows minimal cord swelling no longer suggesting active residual cavernoma ( fig . a 10-year - old girl complaining about dorsalgia for several days suddenly developed lower body dysesthesias and a paraparesis . an l1 sensory - motor level , lower limb hyperreflexia including babinski s signs , and decreased rectal sphincter tone were noted . emergency mr demonstrated hematomyelia ( t8t11 ) , intramedullary edema ( t6l1 ) , and an imc at t9t10 ( fig . within 2  h after admission , paraparesis progressed to paraplegia , and therefore , the girl was operated immediately . 1a1a3 preoperative sagittal t1 , t2 , and t2 ffe ( fast field echo ) mr images revealing a markedly swollen cord , including intramedullary edema ( t6l1 ) , hematomyelia ( t8t11 ) , and an imc at t9t10 ; b1b3 3  months postoperative sagittal t1 , t2 , and axial t2 mr images confirming complete resection ; c1c3 2  years postoperative sagittal t1 , t2 , and axial t2 mr images demonstrating a thin spinal cord without evidence of local recurrence ; d1 , d2 2  years postoperative anteroposterior and lateral spinal x - rays to monitor kyphoscoliosis a1a3 preoperative sagittal t1 , t2 , and t2 ffe ( fast field echo ) mr images revealing a markedly swollen cord , including intramedullary edema ( t6l1 ) , hematomyelia ( t8t11 ) , and an imc at t9t10 ; b1b3 3  months postoperative sagittal t1 , t2 , and axial t2 mr images confirming complete resection ; c1c3 2  years postoperative sagittal t1 , t2 , and axial t2 mr images demonstrating a thin spinal cord without evidence of local recurrence ; d1 , d2 2  years postoperative anteroposterior and lateral spinal x - rays to monitor kyphoscoliosis we had no time to localize the lesion preoperatively . consequently , we removed three thoracic laminae and two more after durotomy revealing insufficient exposure of the lesion , which appeared as a dark blue clot shining through the pia mater . after midline myelotomy , the hematoma presented itself , and the cavernoma was gently mobilized and resected . the girl slowly recovered , regaining minimal voluntary movement after 10  days , continence after 9  months , and independent ambulation after 12  months . 1b ) , whereas 2  years postoperative mr shows a thin spinal cord without evidence of local recurrence ( fig . a 10-year - old girl complaining about dorsalgia for several days suddenly developed lower body dysesthesias and a paraparesis . an l1 sensory - motor level , lower limb hyperreflexia including babinski s signs , and decreased rectal sphincter tone were noted . emergency mr demonstrated hematomyelia ( t8t11 ) , intramedullary edema ( t6l1 ) , and an imc at t9t10 ( fig . within 2  h after admission , paraparesis progressed to paraplegia , and therefore , the girl was operated immediately . 1a1a3 preoperative sagittal t1 , t2 , and t2 ffe ( fast field echo ) mr images revealing a markedly swollen cord , including intramedullary edema ( t6l1 ) , hematomyelia ( t8t11 ) , and an imc at t9t10 ; b1b3 3  months postoperative sagittal t1 , t2 , and axial t2 mr images confirming complete resection ; c1c3 2  years postoperative sagittal t1 , t2 , and axial t2 mr images demonstrating a thin spinal cord without evidence of local recurrence ; d1 , d2 2  years postoperative anteroposterior and lateral spinal x - rays to monitor kyphoscoliosis a1a3 preoperative sagittal t1 , t2 , and t2 ffe ( fast field echo ) mr images revealing a markedly swollen cord , including intramedullary edema ( t6l1 ) , hematomyelia ( t8t11 ) , and an imc at t9t10 ; b1b3 3  months postoperative sagittal t1 , t2 , and axial t2 mr images confirming complete resection ; c1c3 2  years postoperative sagittal t1 , t2 , and axial t2 mr images demonstrating a thin spinal cord without evidence of local recurrence ; d1 , d2 2  years postoperative anteroposterior and lateral spinal x - rays to monitor kyphoscoliosis consequently , we removed three thoracic laminae and two more after durotomy revealing insufficient exposure of the lesion , which appeared as a dark blue clot shining through the pia mater . after midline myelotomy , the hematoma presented itself , and the cavernoma was gently mobilized and resected . the girl slowly recovered , regaining minimal voluntary movement after 10  days , continence after 9  months , and independent ambulation after 12  months . 1b ) , whereas 2  years postoperative mr shows a thin spinal cord without evidence of local recurrence ( fig . one day after a fall during skating , a 7-year - old girl suddenly developed cervicalgia and severe paresis of her left arm and leg ( grades 12 out of 5 according to the american spinal injury association ) . her paresis improved to a grade 4 , and at 3  months , her residual deficit was minimal . 2a1a3 preoperative sagittal t1 , t2 , and axial t2 mr images revealing a markedly swollen cord , including hematomyelia at c4c6 and a left anterolateral imc at c5 ; b1 , b2 3  months postoperative sagittal t2 and axial t2 ffe ( fast field echo ) mr images , note multiple small cerebral cavernomas ; c1 , c2 2.5  years postoperative sagittal and axial t2 mr images , the cord still appears swollen ; d1 , d2 3.5  years postoperative sagittal and axial t2 mr images , the cord now appears less swollen and the child is asymptomatic a1a3 preoperative sagittal t1 , t2 , and axial t2 mr images revealing a markedly swollen cord , including hematomyelia at c4c6 and a left anterolateral imc at c5 ; b1 , b2 3  months postoperative sagittal t2 and axial t2 ffe ( fast field echo ) mr images , note multiple small cerebral cavernomas ; c1 , c2 2.5  years postoperative sagittal and axial t2 mr images , the cord still appears swollen ; d1 , d2 3.5  years postoperative sagittal and axial t2 mr images , the cord now appears less swollen and the child is asymptomatic at that time , she was operated using a c3c7 laminoplastic technique and motor evoked potential monitoring . the cord at c4c5 was clearly swollen , and the exact position of the cavernoma was determined using ultrasonography ( fig . subtle subpial yellow - blue discoloration was apparent after sectioning the left c4c5 denticulate ligament and gently rotating the spinal cord to the right ( fig . after lateral myelotomy , the hematoma presented itself ; however , mobilizing and resecting the cavernoma was difficult due to a rather limited lateromedial view inside the spinal cord . 3a macroscopic intraoperative image at c4c5 ( left dorsolateral view , one denticulate ligament sectioned ) showing subtle subpial yellow - blue discoloration at the lateral surface of the spinal cord . b ultrasonic intraoperative image at c3c6 ( sagittal view ) specifying the exact location of the cavernoma in the swollen cord segment a macroscopic intraoperative image at c4c5 ( left dorsolateral view , one denticulate ligament sectioned ) showing subtle subpial yellow - blue discoloration at the lateral surface of the spinal cord . b ultrasonic intraoperative image at c3c6 ( sagittal view ) specifying the exact location of the cavernoma in the swollen cord segment the girl did well after the operation showing no new neurological deficits . multiple small cerebral cavernomas and a familial autosomal cavernous malformation syndrome were diagnosed with mutation of the mgc4607/malcavernin / ccm2-gen ( fig . the following 1.5  years , she complained of intermittent cervicalgia and left brachial dysesthesias , with mr suggesting active residual cavernoma ( fig .  2c ) . mr after 3.5  years shows minimal cord swelling no longer suggesting active residual cavernoma ( fig . one day after a fall during skating , a 7-year - old girl suddenly developed cervicalgia and severe paresis of her left arm and leg ( grades 12 out of 5 according to the american spinal injury association ) . her paresis improved to a grade 4 , and at 3  months , her residual deficit was minimal . 2a1a3 preoperative sagittal t1 , t2 , and axial t2 mr images revealing a markedly swollen cord , including hematomyelia at c4c6 and a left anterolateral imc at c5 ; b1 , b2 3  months postoperative sagittal t2 and axial t2 ffe ( fast field echo ) mr images , note multiple small cerebral cavernomas ; c1 , c2 2.5  years postoperative sagittal and axial t2 mr images , the cord still appears swollen ; d1 , d2 3.5  years postoperative sagittal and axial t2 mr images , the cord now appears less swollen and the child is asymptomatic a1a3 preoperative sagittal t1 , t2 , and axial t2 mr images revealing a markedly swollen cord , including hematomyelia at c4c6 and a left anterolateral imc at c5 ; b1 , b2 3  months postoperative sagittal t2 and axial t2 ffe ( fast field echo ) mr images , note multiple small cerebral cavernomas ; c1 , c2 2.5  years postoperative sagittal and axial t2 mr images , the cord still appears swollen ; d1 , d2 3.5  years postoperative sagittal and axial t2 mr images , the cord now appears less swollen and the child is asymptomatic at that time , she was operated using a c3c7 laminoplastic technique and motor evoked potential monitoring . the cord at c4c5 was clearly swollen , and the exact position of the cavernoma was determined using ultrasonography ( fig . subtle subpial yellow - blue discoloration was apparent after sectioning the left c4c5 denticulate ligament and gently rotating the spinal cord to the right ( fig . after lateral myelotomy , the hematoma presented itself ; however , mobilizing and resecting the cavernoma was difficult due to a rather limited lateromedial view inside the spinal cord . 3a macroscopic intraoperative image at c4c5 ( left dorsolateral view , one denticulate ligament sectioned ) showing subtle subpial yellow - blue discoloration at the lateral surface of the spinal cord . b ultrasonic intraoperative image at c3c6 ( sagittal view ) specifying the exact location of the cavernoma in the swollen cord segment a macroscopic intraoperative image at c4c5 ( left dorsolateral view , one denticulate ligament sectioned ) showing subtle subpial yellow - blue discoloration at the lateral surface of the spinal cord . b ultrasonic intraoperative image at c3c6 ( sagittal view ) specifying the exact location of the cavernoma in the swollen cord segment multiple small cerebral cavernomas and a familial autosomal cavernous malformation syndrome were diagnosed with mutation of the mgc4607/malcavernin / ccm2-gen ( fig . the following 1.5  years , she complained of intermittent cervicalgia and left brachial dysesthesias , with mr suggesting active residual cavernoma ( fig .  2c ) . mr after 3.5  years shows minimal cord swelling no longer suggesting active residual cavernoma ( fig . imc are rare lesions in adults but even more in children , representing 5% and 1% , respectively , of all intramedullary lesions at tertiary referral centers [ 5 , 23 ] . as such , less than 20 symptomatic children have been reported in the english literature [ 1 , 2 , 6 , 9 , 10 , 16 , 1820 , 2325 ] ( table  1 ) , invariably presenting with an acute , severe neurological deficit followed by rapid deterioration due to hematomyelia . adults , on the other hand , present with slowly progressive deficits or an acute deficit followed by a slow , stepwise deterioration with episodes of some clinical improvement , caused by repeated microhemorrhage followed by gliosis or iterative thrombosis within the cavernoma [ 8 , 15 , 19 ] . our first patient complained about dorsalgia for several days and then suddenly developed lower body dysesthesias and a paraparesis , which within 2  h after admission progressed to paraplegia . our second patient suddenly developed cervicalgia and severe paresis of her left arm and leg 1  day after a fall . the acute presentation in both cases is in line with the literature ; however , the second patient remained in stable clinical condition over the following days and therefore did not require emergency surgery . the clinical presentation of imc in general is quite variable , often including both sensory and motor symptoms , resulting in pain and paresis . as such , zevgaridis et al .   distinguished three major patterns in the clinical course of 117 symptomatic imc in patients between 12 and 88  years old . group a ( 30% ) suffered multiple episodes of discrete neurological deterioration and varying degrees of recovery in between . group c ( 26% ) suffered sudden onset of symptoms and rapid decline over hours or days ( c1 , 16% ) , which is common in children [ 10 , 18 ] , or a little slower over several weeks ( c2 , 10% ) . most clinical series deal mainly or exclusively with adult patients and demonstrate a higher bleeding risk ( regardless of age ) for imc as compared to their cerebral counterparts : the annual bleeding risk for cerebral cavernomas is believed to be about 0.71.3% [ 3 , 13 , 21 ] , for brainstem cavernomas about 2.7% , and for imc about 1.64.5% [ 18 , 19 , 22 ] . moreover , the potential that hemorrhage may cause significant morbidity is higher for imc than for their cerebral counterparts because of the confined parenchymatous space in which imc are located . deutsch et al .   postulated that adult imc are equally distributed among both sexes ; however , a female predisposition in those presenting with hemorrhage ( female / male ratio 2:1 )   may be attributable to a hormonal effect increasing the risk of hemorrhage . more recently , santoro et al .   performed an extensive literature review and calculated a female / male ratio of 1.1:1 . in contrast , a male predisposition is reported in children ( female / male ratio 1:2 ) , and the mean age they present with hematomyelia is 9.1  years ( range 7  months17  years ) according to scott et al .   or 13.2  years ( range 817  years ) according to noudel et al . . in this regard , some authors believe that hormonal factors may influence the clinical onset of cavernomas in puberty . our report adds two girls to the literature and challenges the reported male predisposition in children ( table  1 ) . mr is the golden standard to diagnose cavernomas in any location , as myelography and computed tomography are much less sensitive   and cavernomas are angiographically occult . imc typically have a mixed signal intensity on mr scans , including a hyperintense core lesion and a rim of low signal intensity caused by hemosiderin deposition around the cavernoma on t2-weighted images . their size varies from 0.85.4  cm ( mean 1.41.7  cm ) [ 3 , 5 , 10 , 15 ] , and typically , they are small , round , or ovoid well - defined lesions [ 5 , 10 ] situated dorsolaterally in the spinal cord   where they may reach the surface . the imc in our patients were of intermediate size and situated dorsomedially ( case 1 ) and left ( dorso)laterally ( case 2 ) . the extent of hematomyelia ( t8t11 ) and intramedullary edema ( t6l1 ) in the former patient , however , made an exact delineation of the cavernoma difficult . according to the literature , imc in adults are more common in the thoracic cord , whereas imc in children are equally distributed in the cervical and thoracic cord [ 18 , 19 ] ( table  1 ) . as such , our first patient had a cavernoma at t9t10 and our second patient at c5 . importantly , imc may occur in association with cerebral or systemic lesions [ 1 , 10 ] . multiple lesions are typically seen in the so - called inherited cerebral cavernous malformation disorder , which was diagnosed in our second patient . to date , three loci have been identified for this disorder : ccm1 on chromosome arm 7q , ccm2 on 7p ( our second patient ) , and ccm3 on 3q , which may be responsible for approximately 4050% , 1020% , and 40% of inherited cases , respectively [ 4 , 7 ] . in fact , as many as 1240% [ 5 , 10 ] of patients and especially children and young adults with imc have other cavernomas in their central nervous system ( table  1 ) . complete neuraxis imaging in all patients and particularly in the younger age group is therefore mandatory [ 10 , 27 ] . few cases have been reported with multifocal ( intramedullary and cerebral ) cavernomas yet without a positive family history , and several theories have been proposed to explain their occurrence : a neoplast - like process with hormonal influence during pregnancy , the possible seeding of a lesion along a biopsy track , the intralesional presence of endothelial cell expressing proliferating cell nuclear antigen , the occurrence of cavernomas in areas previously irradiated , and an incomplete penetrance or even a misdiagnosis of the disease [ 17 , 23 , 28 ] . some authors recommend resection for every patient with symptomatic imc and even for those who have minimal symptoms [ 10 , 24 ] . they argue that once symptoms and signs caused by hemorrhage have appeared , the patient will likely experience future neurological decline , whereas after microsurgical resection by experienced hands , a stable or improved functional status is achieved in 9294% of patients [ 10 , 29 ] independent of age , gender , and lesion location . on the other hand , kharkar et al . recently evaluated the natural history of conservatively managed symptomatic imc and did not observe a significant , permanent neurological decline in a cohort of ten patients during a mean follow - up period of 80  months . of note , all but one were adult patients who may have a different clinical course as previously outlined , and the study design was retrospective nonrandomized ( conservatively managed patients presenting mainly with paresthesias , surgically managed patients presenting mainly with pain and paresis ) . the authors carefully conclude that they may have identified a distinct subgroup of patients with symptomatic imc that may have a much lower risk of rehemorrhage . most neurosurgeons would agree that dissection must be confined to the thin layer of hemosiderin laden gliosis surrounding the imc to limit damage to the normal adjacent spinal cord tissue . according to some authors , this would even obviate the use of neurophysiological monitoring which they consider time - consuming and of debated reliability . others including us prefer neurophysiological monitoring for every elective intramedullary resective procedure [ 6 , 10 , 14 ] . furthermore , intraoperative ultrasound typically shows a hypointense signal at the site of recent hemorrhage , helps to localize the lesion if not readily visible on the cord surface , and helps to determine the optimal entry point to approach the lesion . there is considerably more debate regarding the optimal timing for resection , which is simply not known , and factors such as severity of the patients clinical condition , presence ( or absence ) of clinical progression , anatomical level of the lesion , and attending surgeons experience would be taken into account . some authors propose 4 to 6  weeks after hemorrhage as an optimal time to operate , as during such time interval , a gliotic plane would have formed around the cavernoma , enabling the surgeon to safely separate cavernoma from surrounding cord tissue [ 10 , 12 , 29 ] . this is exactly what we did in case 2 , who remained in stable clinical condition initially and then gradually recovered until she was operated 3  months after hemorrhage . in case 1 who rapidly progressed to paraplegia , we did not hesitate to operate immediately , and fortunately , the girl demonstrated remarkable recovery regaining continence and independent ambulation over the following months . in fact , in such situation , there may be imminent spinal cord infarction due to a steep pressure rise in the spinal cord , which is lined by nonelastic pia mater . therefore , rapid pressure relief may be the only way to prevent irreversible spinal cord infarction . it is essential to achieve radical removal during the first operation because any imc residue may lead to further hemorrhage , and a second operation may present greater surgical difficulties . rebleeding risk may be as high as 17.6% according to vishteh et al .   or even 66% according to sandalcioglu et al .   and may cause recurrent myelopathy ( 9% ) . whereas our first patient clearly has no residual cavernoma on postoperative mr scans , our second patient seemed to have an actively leaking residual cavernoma on initial follow - up mr scans and complained of intermittent cervicalgia and left brachial dysesthesias for approximately 1.5  years postoperatively . mr after 3.5  years shows minimal cord swelling no longer suggesting active residual cavernoma . little if anything is found in the literature concerning the difficult dilemma between follow - up and reoperation in case of residual cavernoma , especially in the setting of multiple cavernomas in children who have a long life expectancy and are otherwise doing fine . it is generally believed subtotally resected lesions and/or syndromal cases tend to recur [ 1 , 10 , 12 , 18 , 24 , 26 ] . in this regard , scott et al .   have suggested that central nervous system cavernomas may frequently bleed silently , producing low - pressure small - volume hemorrhages which are radiologically invisible . such hemorrhages may not be of a critical volume or may not be in a critical location and therefore may not be life threatening ; however , they may expand with time and irritate the spinal cord , which may become gliotic and edematous [ 10 , 24 ] . on the other hand , one should keep in mind that especially early postoperative mr images may be misleading and therefore misinterpreted , as low - intensity signals of postoperative scar tissue may be misdiagnosed for residual cavernoma and that mr images may become more reliable at least 6  months postoperatively . clearly , definitive answers await more cases with longer follow - up , and until then , surgical decisions have to be made on a case - by - case basis . finally , therapeutic indications remain controversial for asymptomatic imc in sporadic as well as nonsporadic cases . some recommend surgical resection for readily accessible imc [ 5 , 6 , 22 ] , whereas others recommend an expectant policy and regular clinicoradiological follow - up for deeper lesions [ 13 , 10 , 12 ] . reported delayed complications in four of 17 patients ( 23.5% ) with surgically treated imc . these complications were mainly symptomatic rehemorrhage as a result of incomplete resection , or less frequently symptomatic spinal cord tethering . clinical symptoms of spinal cord tethering include severe headaches , neck pain , arm or leg pain irresponsive to medical therapy , and/or progressive neurological deficit , which are all related to the level of spinal cord tethering . surgical detethering is indicated in patients who develop new or progressive symptoms in the late postoperative period and are radiographically suspect for tethering . in children , spinal deformity is another potential complication after multilevel laminectomy . as children may develop delayed spinal deformity and/or spinal cord tethering during longitudinal growth , regular radiological follow - up imc are rare lesions in adults but even more in children , representing 5% and 1% , respectively , of all intramedullary lesions at tertiary referral centers [ 5 , 23 ] . as such , less than 20 symptomatic children have been reported in the english literature [ 1 , 2 , 6 , 9 , 10 , 16 , 1820 , 2325 ] ( table  1 ) , invariably presenting with an acute , severe neurological deficit followed by rapid deterioration due to hematomyelia . adults , on the other hand , present with slowly progressive deficits or an acute deficit followed by a slow , stepwise deterioration with episodes of some clinical improvement , caused by repeated microhemorrhage followed by gliosis or iterative thrombosis within the cavernoma [ 8 , 15 , 19 ] . our first patient complained about dorsalgia for several days and then suddenly developed lower body dysesthesias and a paraparesis , which within 2  h after admission progressed to paraplegia . our second patient suddenly developed cervicalgia and severe paresis of her left arm and leg 1  day after a fall . the acute presentation in both cases is in line with the literature ; however , the second patient remained in stable clinical condition over the following days and therefore did not require emergency surgery . the clinical presentation of imc in general is quite variable , often including both sensory and motor symptoms , resulting in pain and paresis . as such , zevgaridis et al .   distinguished three major patterns in the clinical course of 117 symptomatic imc in patients between 12 and 88  years old . group a ( 30% ) suffered multiple episodes of discrete neurological deterioration and varying degrees of recovery in between . group c ( 26% ) suffered sudden onset of symptoms and rapid decline over hours or days ( c1 , 16% ) , which is common in children [ 10 , 18 ] , or a little slower over several weeks ( c2 , 10% ) . most clinical series deal mainly or exclusively with adult patients and demonstrate a higher bleeding risk ( regardless of age ) for imc as compared to their cerebral counterparts : the annual bleeding risk for cerebral cavernomas is believed to be about 0.71.3% [ 3 , 13 , 21 ] , for brainstem cavernomas about 2.7% , and for imc about 1.64.5% [ 18 , 19 , 22 ] . moreover , the potential that hemorrhage may cause significant morbidity is higher for imc than for their cerebral counterparts because of the confined parenchymatous space in which imc are located . deutsch et al .   postulated that adult imc are equally distributed among both sexes ; however , a female predisposition in those presenting with hemorrhage ( female / male ratio 2:1 )   may be attributable to a hormonal effect increasing the risk of hemorrhage . more recently , santoro et al .   performed an extensive literature review and calculated a female / male ratio of 1.1:1 . in contrast , a male predisposition is reported in children ( female / male ratio 1:2 ) , and the mean age they present with hematomyelia is 9.1  years ( range 7  months17  years ) according to scott et al .   or 13.2  years ( range 817  years ) according to noudel et al . . in this regard , some authors believe that hormonal factors may influence the clinical onset of cavernomas in puberty . our report adds two girls to the literature and challenges the reported male predisposition in children ( table  1 ) . mr is the golden standard to diagnose cavernomas in any location , as myelography and computed tomography are much less sensitive   and cavernomas are angiographically occult . imc typically have a mixed signal intensity on mr scans , including a hyperintense core lesion and a rim of low signal intensity caused by hemosiderin deposition around the cavernoma on t2-weighted images . their size varies from 0.85.4  cm ( mean 1.41.7  cm ) [ 3 , 5 , 10 , 15 ] , and typically , they are small , round , or ovoid well - defined lesions [ 5 , 10 ] situated dorsolaterally in the spinal cord   where they may reach the surface . the imc in our patients were of intermediate size and situated dorsomedially ( case 1 ) and left ( dorso)laterally ( case 2 ) . the extent of hematomyelia ( t8t11 ) and intramedullary edema ( t6l1 ) in the former patient , however , made an exact delineation of the cavernoma difficult . according to the literature , imc in adults are more common in the thoracic cord , whereas imc in children are equally distributed in the cervical and thoracic cord [ 18 , 19 ] ( table  1 ) . as such , our first patient had a cavernoma at t9t10 and our second patient at c5 . importantly , imc may occur in association with cerebral or systemic lesions [ 1 , 10 ] . multiple lesions are typically seen in the so - called inherited cerebral cavernous malformation disorder , which was diagnosed in our second patient . to date , three loci have been identified for this disorder : ccm1 on chromosome arm 7q , ccm2 on 7p ( our second patient ) , and ccm3 on 3q , which may be responsible for approximately 4050% , 1020% , and 40% of inherited cases , respectively [ 4 , 7 ] . in fact , as many as 1240% [ 5 , 10 ] of patients and especially children and young adults with imc have other cavernomas in their central nervous system ( table  1 ) . complete neuraxis imaging in all patients and particularly in the younger age group is therefore mandatory [ 10 , 27 ] . few cases have been reported with multifocal ( intramedullary and cerebral ) cavernomas yet without a positive family history , and several theories have been proposed to explain their occurrence : a neoplast - like process with hormonal influence during pregnancy , the possible seeding of a lesion along a biopsy track , the intralesional presence of endothelial cell expressing proliferating cell nuclear antigen , the occurrence of cavernomas in areas previously irradiated , and an incomplete penetrance or even a misdiagnosis of the disease [ 17 , 23 , 28 ] . some authors recommend resection for every patient with symptomatic imc and even for those who have minimal symptoms [ 10 , 24 ] . they argue that once symptoms and signs caused by hemorrhage have appeared , the patient will likely experience future neurological decline , whereas after microsurgical resection by experienced hands , a stable or improved functional status is achieved in 9294% of patients [ 10 , 29 ] independent of age , gender , and lesion location . on the other hand , kharkar et al . recently evaluated the natural history of conservatively managed symptomatic imc and did not observe a significant , permanent neurological decline in a cohort of ten patients during a mean follow - up period of 80  months . of note , all but one were adult patients who may have a different clinical course as previously outlined , and the study design was retrospective nonrandomized ( conservatively managed patients presenting mainly with paresthesias , surgically managed patients presenting mainly with pain and paresis ) . the authors carefully conclude that they may have identified a distinct subgroup of patients with symptomatic imc that may have a much lower risk of rehemorrhage . most neurosurgeons would agree that dissection must be confined to the thin layer of hemosiderin laden gliosis surrounding the imc to limit damage to the normal adjacent spinal cord tissue . according to some authors , this would even obviate the use of neurophysiological monitoring which they consider time - consuming and of debated reliability . others including us prefer neurophysiological monitoring for every elective intramedullary resective procedure [ 6 , 10 , 14 ] . furthermore , intraoperative ultrasound typically shows a hypointense signal at the site of recent hemorrhage , helps to localize the lesion if not readily visible on the cord surface , and helps to determine the optimal entry point to approach the lesion . there is considerably more debate regarding the optimal timing for resection , which is simply not known , and factors such as severity of the patients clinical condition , presence ( or absence ) of clinical progression , anatomical level of the lesion , and attending surgeons experience would be taken into account . some authors propose 4 to 6  weeks after hemorrhage as an optimal time to operate , as during such time interval , a gliotic plane would have formed around the cavernoma , enabling the surgeon to safely separate cavernoma from surrounding cord tissue [ 10 , 12 , 29 ] . this is exactly what we did in case 2 , who remained in stable clinical condition initially and then gradually recovered until she was operated 3  months after hemorrhage . in case 1 who rapidly progressed to paraplegia , we did not hesitate to operate immediately , and fortunately , the girl demonstrated remarkable recovery regaining continence and independent ambulation over the following months . in fact , in such situation , there may be imminent spinal cord infarction due to a steep pressure rise in the spinal cord , which is lined by nonelastic pia mater . therefore , rapid pressure relief may be the only way to prevent irreversible spinal cord infarction . it is essential to achieve radical removal during the first operation because any imc residue may lead to further hemorrhage , and a second operation may present greater surgical difficulties . rebleeding risk may be as high as 17.6% according to vishteh et al .   or even 66% according to sandalcioglu et al .   and may cause recurrent myelopathy ( 9% ) . whereas our first patient clearly has no residual cavernoma on postoperative mr scans , our second patient seemed to have an actively leaking residual cavernoma on initial follow - up mr scans and complained of intermittent cervicalgia and left brachial dysesthesias for approximately 1.5  years postoperatively . mr after 3.5  years shows minimal cord swelling no longer suggesting active residual cavernoma . little if anything is found in the literature concerning the difficult dilemma between follow - up and reoperation in case of residual cavernoma , especially in the setting of multiple cavernomas in children who have a long life expectancy and are otherwise doing fine . it is generally believed subtotally resected lesions and/or syndromal cases tend to recur [ 1 , 10 , 12 , 18 , 24 , 26 ] . in this regard , scott et al .   have suggested that central nervous system cavernomas may frequently bleed silently , producing low - pressure small - volume hemorrhages which are radiologically invisible . such hemorrhages may not be of a critical volume or may not be in a critical location and therefore may not be life threatening ; however , they may expand with time and irritate the spinal cord , which may become gliotic and edematous [ 10 , 24 ] . on the other hand , one should keep in mind that especially early postoperative mr images may be misleading and therefore misinterpreted , as low - intensity signals of postoperative scar tissue may be misdiagnosed for residual cavernoma and that mr images may become more reliable at least 6  months postoperatively . clearly , definitive answers await more cases with longer follow - up , and until then , surgical decisions have to be made on a case - by - case basis . finally , therapeutic indications remain controversial for asymptomatic imc in sporadic as well as nonsporadic cases . some recommend surgical resection for readily accessible imc [ 5 , 6 , 22 ] , whereas others recommend an expectant policy and regular clinicoradiological follow - up for deeper lesions [ 13 , 10 , 12 ] . vishteh et al .   reported delayed complications in four of 17 patients ( 23.5% ) with surgically treated imc . these complications were mainly symptomatic rehemorrhage as a result of incomplete resection , or less frequently symptomatic spinal cord tethering . clinical symptoms of spinal cord tethering include severe headaches , neck pain , arm or leg pain irresponsive to medical therapy , and/or progressive neurological deficit , which are all related to the level of spinal cord tethering . surgical detethering is indicated in patients who develop new or progressive symptoms in the late postoperative period and are radiographically suspect for tethering . in children , as children may develop delayed spinal deformity and/or spinal cord tethering during longitudinal growth , regular radiological follow - up is indicated until they have reached adult stature ( fig . less than 20 children with imc have been reported in the english literature ; however , cases with an unfavorable outcome may be underreported . we report two girls presenting with an acute , severe neurological deficit due to hematomyelia , thereby challenging the male predominance in this age group . mr of the entire neuraxis is mandatory , as these children are more likely to harbor a familial autosomal cavernous malformation syndrome . with adequate surgical treatment either in the acute phase or after clinical recuperation definitive answers await more cases with longer follow - up especially after subtotal resection ; however , as long as patients remain in stable condition , careful clinical and radiological follow - up may be an alternative to reoperation .