a 36-year - old man with an itching and tingling sensation in the left l2 dermatome area for 3 months was referred to our clinic for pain management .
the patient did not have significant past medical history , and before coming to the clinic , he had been treated with gabapentin 600 mg 3 times a day by a dermatologist but the symptoms were not improved .
there were no unusual finding in the biopsy other than subcorneal pustules , hyperkeratosis and parakeratosis ; therefore , he was referred to our department for pain control .
he was also complaining of allodynia and paresthesia , and his visual analogue scale ( vas ) was 2 out of 10 ( 0 = no pain , 10 = worst possible pain ) .
his motor function was intact and there was no sensory loss . his knee jerk reflex was increased ( 3+/3 + ) thus a thoraco - lumbar spine magnetic resonance imaging ( t - l mri ) was performed due to suspicion of an upper motor neuron ( umn ) lesion . in the mri , an intramedullary lesion 1.2 cm in size was found in the dorsal subpial surface of the t11 - 12 level , and this was diagnosed as type ii avm in the t11/12 level of the spinal cord ( fig .
a spinal angiography was performed on the patient and the results revealed that the lesion was a spinal cord avm supplied by the anterior spinal artery from the left t9 intercostal artery .
it was also contrasted from the left l1 lumbar artery ( artery of adamkiewicz ) ( fig .
the patient was transferred to another hospital for removal of avm with cyber knife , and after the operation , the symptoms were improved .
laboratory tests are the tzank smear , a serological test such as the indirect fluorescent antibody method , and detection through molecular biology or immunology such as tissue cultures .
a dermatomal rash is not present in zsh so it is difficult to suspect hz , and hence , serological , immunological , or molecular biological tests are not performed during the acute phase .
only when the pain continues chronically are many cases diagnosed by the characteristics of pain .
however , when a patient complains of continuing dermatomal neuropathic pain , a detailed history taking and accurate physical examination should be done to differentiate zsh from sciatica , collapsed intervertebral disc , spinal stenosis , tumor , angina , renal colic , cholecystitis , costochondritis , intercostal neuralgia , entrapment syndrome , pleurodynia , myofascial pain syndrome , and other neuropathic pain before diagnosis . in this case , the patient complained of tingling pain with a vas score of 2 and accompanying itching , paresthesia , and allodynia in the left l2 dermatome for 3 months . during the physical examination ,
motor and sensory function was intact but the knee jerk reflex was increased to 3 + on both sides .
hence , an umn lesion above the l2 level was suspected , an avm in the t11/12 level was discovered in the t - l mri .
the umn is the pathway from the brain and brainstem to the anterior horn of the spinal cord .
the lower motor neuron ( lmn ) is the pathway from the anterior horn of the spinal cord to the skeletal muscles . in this case , only the knee jerk reflex was hyperactive with l2 dermatomal pain without any other general symptoms or symptoms in the upper extremity .
therefore , a spinal cord lesion in a level higher than the l2 level was anticipated , and a t - l mri was performed to diagnose the avm .
other symptoms that suggest an umn lesion are weakness , paralysis , spasticity , and muscle atrophy , but these symptoms were not observed in our patient .
only the hyperactivity of the knee jerk reflex was observed , but if the babinski response ( the most sensitive indicator of the umn ) had been checked , it would have been more helpful in making the diagnosis .
avm is the abnormal development of blood vessels which occurs during the 4th to 8th week of embryonic development when blood vessels are differentiated into arteries , veins , and capillaries .
normally arteries and veins are connected by capillaries , but there is no true capillary bed in avm ; thus over time , a tangle is formed in the blood vessel connecting the artery and vein . therefore ,
oxygenated arterial blood is shunted and supplied directly into the venous system which can cause temporary or permanent ischemia in the surrounding tissue .
avm can develop anywhere in the body and there can be various manifestations of symptoms according to the location and blood flow . usually , it develops in the limbs , neck , and face , and it can cause pain , congestive heart failure , and hypotension from vascular congestion and so on .
cerebral avm can cause seizure or severe headaches , but mostly there are no symptoms .
spinal avm has a prevalence of approximately 10% for cerebral avm and less than 5% for an intraspinal mass . as in this case
, it usually occurs in middle - aged men in the lower thoracic or lumbar region .
typical early symptoms are dermatomal lancinating pain , weakness / paralysis , numbness , and paresthesia [ 9 - 11 ] . spinal avm
glomus - type ( type 2 ) with a tightly compacted group of arterial and venous vessels inside a short segment of the spinal cord , and usually , it is supplied by one artery .
spinal avm is very rare with a prevalence of less than 1% , shows various clinical symptoms , and is difficult to differentiate from other diseases such as tumors , herniated nucleus pulposus , multiple sclerosis , meningovascular syphilis , tuberculosis , and transverse myelitis .
however subarachnoid hemorrhage or spinal cord hemorrhage due to avm rupture and the subsequent acute neurologic deficit are increasing by 2 - 3% every year , and the mortality at first hemorrhage reaches 10 - 30% ; therefore , an accurate differential diagnosis is very important .
additionally , in this case , the avm was discovered in the mri , but there are many cases which can not be detected by mri thus an angiography must be performed for diagnosis . in this case ,
spinal avm was accurately diagnosed through a detailed neurologic examination , and the appropriate treatment was given .
therefore , when a patient complains of dermatomal neuropathic pain without a rash , a detailed and accurate physical examination should be performed before diagnosing zsh , and laboratory tests should be performed for the acute phase to differentiate it from other diseases that cause neuropathic pain .
 zoster sine herpete ( zsh ) is difficult to diagnosis during an acute period due to the absence of the characteristic zosteriform dermatomal rash ; therefore , progression to postherpetic neuralgia is more common than typical zoster . 
 in addition , misdiagnosis of other neuropathic pain as zsh is common in clinical situations . here 
 , we report a case of spinal arteriovenous malformation that mimics zsh . 
 this is a rare condition ; therefore , high clinical suspicion for a correct diagnosis and proper examination are not easy . however , 
 early diagnosis and definitive treatment are essential to prevent neurologic deficit and mortality . 
CASE REPORT
DISCUSSION