hypertrophic pachymeningitis ( hp ) is a rare disease , and it is characterized by chronic progressive inflammatory fibrosis and thickening of the dura mater with resultant compression of the spinal cord or brain1118 ) . although accessibility and imaging techniques including magnetic resonance ( mr ) imaging have improved recently , it can be missed or it can go unrecognized because of its indolent and non - specific symptoms5 ) . syphilis , tuberculous infection , fungal infection , and autoimmune disorders such as rheumatoid arthritis or wegener 's granulomatosis can be the possible causes571118 ) . however , the majority of cases have no identifiable causes and are called idiopathic hp ( ihp)11 ) . it can occur in the intracranial or spinal dura mater alone or as a craniospinal form18 ) . the spinal form is rarer than the cranial form and only a few cases of the craniospinal form of ihp have been reported11518 ) . here , we report a rare case of ihp in the craniocervical junction involving both the cranial and spinal dura mater and discuss the diagnosis and management of ihp . a 67-year - old woman presented with a 3-month history of neck pain and numbness in the upper limb . she had a 1-month history of progressive gait disturbance . on neurological examination , her motor power in the lower extremity was grade 4/4 and she had gait ataxia . mr imaging revealed spinal cord compression by a posterior epidural mass from the occiput to c2 . the lesion showed low signal intensity on t2-weighted images , iso- to low signal intensity on t1-weighted images , and diffuse contrast enhancement with stronger peripheral enhancement on t1-weighted gadolinium - enhanced images ( fig . 1 ) . an epidural abscess or tumor such as extradural en plaque meningioma was suspected , but a definitive diagnosis was not made . she had no fever and a normal white blood cell count , erythrocyte sedimentation rate ( esr ) , and c - reactive protein ( crp ) were found in the blood test . because of worsening neurologic deficit and uncertain diagnosis , surgery was performed without further diagnostic studies . intraoperatively , the dura was found to be diffusely thickened and compressing the underlying spinal cord . the dura was partially resected to the extent of bony decompression , and a duroplasty was performed . microscopic findings revealed densely dispersed mixed inflammatory infiltrates , frequent lymphoplasmacytic cells , exuberant fibroplasia , focally scattered necrosis , and granuloma formation . there was neither an underlying pathogen responsible for infectious disease nor any evidence of other inflammatory disease ( fig . oral steroid was started . however , facial flushing and gastrointestinal discomfort developed and steroid was discontinued on the 3 day . blood tests to evaluate the secondary cause of hp including rheumatoid factor , antinuclear antibody , and serologic test for syphilis were normal , and we concluded that this case was " idiopathic " . postoperatively , she showed gradual improvement in her gait and was discharged 3 weeks later . she had slight numbness in the upper limb and could walk independently at the 2-year - follow - up follow - up imaging study was not performed because of her refusal of the study due to poor economic status and no clinical evidence of recurrence . craniospinal form of ihp or secondary hp is extremely rare and chief complaints and signs are chronic headache , cranial nerve palsies , cervical radiculopathy or myelopathy occurring either alone or in combination , and signs of increased intracranial pressure ( icp)115161718 ) . some authors noted the clinical courses of the patients with craniocervical hp and suggested that cranial hp extends downward to the spine18 ) . however , there was a case report of craniocervical ihp with no clinical and neuroradiologic evidence for this pattern15 ) . in the present case , however , she had no symptoms or signs suggestive of cranial nerve palsy or increased icp . therefore , no clinical evidence of cranial hp extending downward to the spine was found in the present case . in 2007 , pai et al.10 ) reviewed the mr imaging findings of the 14 published cases up to that time . in 12 of 14 patients , a long extramedullary mass of low signal intensity on t2-weighted image and peripheral enhancement with central nonenhancing portion were found10 ) . they noted that this was a specific mr imaging finding highly suggestive of ihp in the spine10 ) . this pattern represents more intense enhancement in a peripheral zone of active inflammation than in a central zone of fibrosis10 ) . however , homogeneous enhancement pattern in ihp is not infrequent371213 ) . hsu et al.3 ) stated that homogeneous enhancement on mr image in a patient with ihp could be mistaken for epidural lymphoma . low signal intensity on t2-weighted image and homogeneous enhancement pattern of the lesion were also found in spinal extradural en plaque meningioma or in diffusely calcified meningioma without dural tail sign89 ) . a case of ihp with non - enhancement on t1-weighted mri was also reported5 ) . although mr imaging is the preferred imaging modality for ihp , the diagnosis can not be made solely based on the radiological findings11 ) . the diagnosis of ihp can be made when all the known etiologies including tumors such as meningioma and lymphoma , infections such as tuberculosis , sarcoidosis , or syphilis , and autoimmune disorders are ruled out and typical pathologic findings are confirmed1118 ) . accordingly , once the imaging study is suspicious of hp , physicians should perform a thorough evaluation to identify or to rule out the secondary causes of hp11 ) . there are few case reports of the spinal form of ihp in which the treatment was started on the basis of imaging study and laboratory findings18 ) . in most of the reported cases , surgery was performed for pathologic diagnosis , decompression due to worsening neurologic deficit or both2571213 ) . surgery serves a dual purpose in immediate decompression of the spinal cord and obtaining a diagnosis in patients with ihp12 ) . in some cases , surgery was performed under the suspicion of abscess , tumor , or epidural hematoma713 ) . in most cases , biopsy or partial resection of the dura mater to the extent of bony decompression was possible because of the diffuse nature or long extent of ihp71213 ) . in the present case , uncertain preoperative diagnosis and progressive gait ataxia in the patient led us to perform surgery for pathologic diagnosis and decompression of the spinal cord . however , postoperative diagnosis was hp and the lesion was only partially resected to the extent of laminectomy and suboccipital craniectomy . however , there is no clear consensus on the dose and duration of steroid therapy1112 ) . in addition , radiotherapy , immunosuppressive therapy such as methotrexate and cyclophosphamide , or empirical antituberculous therapy have also been tried , but , the effect of these therapies still remains obscure1115 ) . as in the above mentioned cases , surgical treatment for pathologic diagnosis and decompression of the spinal cord and subsequent steroid therapy is the optimal therapy at present12 ) . relapse or recurrence is the main problem related to long term prognosis24718 ) . the time interval to relapse is also variable from 1 week to several years after initial treatment4 ) . a case of relapse 17 years after the initial treatment was reported14 ) . some authors suggested that patients with active inflammatory signs such as fever , increased esr , increased crp , or leukocytosis before surgery had a poor prognosis and high recurrence rate than patients without inflammatory signs11 ) . other authors suggested that residual pachymeningitis , arachnoiditis , or short - term use of postoperative steroid could cause rapid relapse and they recommended continuous steroid medication to avoid recurrence41112 ) . however , there was a case report of ihp with no recurrence for 7 years after intravenous dexamethasone for only 1 week6 ) . in the present case , fortunately , no relapse was found clinically for 2 years in spite of residual pachymeningitis and no long - term postoperative steroid therapy . suspicion of ihp , knowledge of characteristic mr imaging findings , and thorough laboratory evaluation for underlying causes are essential for accurate diagnosis . prompt surgery for pathologic diagnosis , decompression of neural structure , or both should be considered especially when radiologic or laboratory diagnosis is uncertain or neurologic deficit presents . postoperative steroid therapy and close monitoring of recurrence are necessary for achieving a good long - term outcome .
idiopathic hypertrophic pachymeningitis ( ihp ) is a rare disease , and it is characterized by chronic progressive inflammatory fibrosis and thickening of the dura mater with resultant compression of the spinal cord or neural structure without any identifiable cause . 
 it can occur in the intracranial or spinal dura mater alone or as a craniospinal form . 
 the spinal form is rarer than the cranial form and the craniospinal form is extremely rare . 
 we report a rare case of ihp in the craniocervical junction involving both the cranial and spinal dura mater and discuss the diagnosis and management of the disease .