the latter may occur in the setting of head trauma , subarachnoid hemorrhage ( sah ) , meningitis , and central nervous system ( cns ) tumor [ 1 , 2 ] . the present report describes two unusual cases of supratentorial extraventricular space - occupying processes : meningioma and glioblastoma multiforme ( gbm ) , which initially presented with nph . a 58-year - old female patient was referred to our clinic with a 6-month history of progressive gait disturbance and urinary incontinence . the neurological exam showed the full clinical picture of nph syndrome , including remarkable dementia which had been completely ignored by the patient and relatives . the computed tomography ( ct ) scan demonstrated marked ventriculomegaly as well as a well - delineated left - side temporoparietal lesion , consistent with a convexity meningioma ( fig . however , lumbar tap was not performed because of the presence of the intracranial space - occupying process . the patient was operated on in march 2010 , with total removal of the tumor . transient right - hand paresis appeared in the early postoperative period , with no change in the nph symptoms . the patient was discharged and scheduled for ventriculoperitoneal shunt placement . however , her family refused any further surgical interventions . surprisingly , 1 month later , the patient presented with significant improvement of the gait difficulties and urinary incontinence . the control ct examination showed no data for residual tumor as well as a slight decrease of the ventricular size ( fig . a 68-year - old male patient was referred to the clinic with an 18-month history of involuntary left arm movements and subsequent development of progressive gait disturbances and urinary incontinence . the neuroimaging studies made before the admission demonstrated communicating hydrocephalus without any clinically significant lesions within the brain parenchyma ( fig . just prior to the hospitalization , the patient started to complain of progressive left arm weakness . the control ct scan revealed a heterodense tumor situated in the right frontotemporal region with compression and dislocation of the adjacent brain structures to the left ( fig . 3c ) . partial excision of the lesion was performed in june 2010 , using frameless stereotaxy technique . histologically , the tumor demonstrated typical features of gbm ( who grade iv glioma ; fig . a 58-year - old female patient was referred to our clinic with a 6-month history of progressive gait disturbance and urinary incontinence . the neurological exam showed the full clinical picture of nph syndrome , including remarkable dementia which had been completely ignored by the patient and relatives . the computed tomography ( ct ) scan demonstrated marked ventriculomegaly as well as a well - delineated left - side temporoparietal lesion , consistent with a convexity meningioma ( fig . however , lumbar tap was not performed because of the presence of the intracranial space - occupying process . the patient was operated on in march 2010 , with total removal of the tumor . transient right - hand paresis appeared in the early postoperative period , with no change in the nph symptoms . the patient was discharged and scheduled for ventriculoperitoneal shunt placement . however , her family refused any further surgical interventions . surprisingly , 1 month later , the patient presented with significant improvement of the gait difficulties and urinary incontinence . the control ct examination showed no data for residual tumor as well as a slight decrease of the ventricular size ( fig . a 68-year - old male patient was referred to the clinic with an 18-month history of involuntary left arm movements and subsequent development of progressive gait disturbances and urinary incontinence . the neuroimaging studies made before the admission demonstrated communicating hydrocephalus without any clinically significant lesions within the brain parenchyma ( fig . just prior to the hospitalization , the patient started to complain of progressive left arm weakness . the control ct scan revealed a heterodense tumor situated in the right frontotemporal region with compression and dislocation of the adjacent brain structures to the left ( fig . partial excision of the lesion was performed in june 2010 , using frameless stereotaxy technique . histologically , the tumor demonstrated typical features of gbm ( who grade iv glioma ; fig . nph is a clinical and radiographic syndrome characterized by ventriculomegaly , gait disturbances , urinary incontinence , and mental decline . the condition may occur due to a variety of secondary causes including head injury , sah , meningitis , and cns tumor [ 1 , 2 ] . a number of possible mechanisms have been suggested to explain the pathogenesis of adult hydrocephalus that occurs in association with intracranial space - occupying processes [ 3 , 4 , 5 , 6 , 7 , 8 ] . the blockage of the csf outflow through the ventricular system is one of the most common pathways for the development of secondary hydrocephalus in adults . the majorities of cases demonstrate rapidly progressing symptoms of increased intracranial pressure and necessitate urgent intervention . however , in some instances , patients may also develop nph , as described by lobato et al .   and sayama et al . obviously , this mechanism is not relevant to our cases , as both tumors were extraventricular . according to many authors , the hyperproteinorrachia , which can be observed in some patients with cns tumors , may cause nph by impairing csf reabsorption at the level of the arachnoid granulations . however , in our cases , this mechanism can only be suspected , because no lumbar puncture was performed before surgery . interestingly , the systematic review of the literature revealed only one such case : a 69-year - old female patient with leptomeningeal gliomatosis , who initially presented with confusion , progressive memory decline , and urinary incontinence . the repeated ct scan demonstrated slight dilatation of the lateral ventricles , which together with the authors clinical description supports the diagnosis of nph , although the latter was not specifically proposed . even possible in our case with gbm , this mechanism remains unproved , because no autopsy was done . the latter may provoke adult hydrocephalus on the basis of a decreased rate of csf absorption at the arachnoid villi . for example , chang et al .   described a 51-year - old male patient with spinal leptomeningeal metastases from a giant - cell gbm , who consequently developed sah and nph . in our cases , however , this mechanism is probably of no significance , because in neither of them subarachnoid bleeding was observed .
normal pressure hydrocephalus ( nph ) is a clinical and radiographic syndrome characterized by ventriculomegaly , abnormal gait , urinary incontinence , and dementia . 
 the condition may occur due to a variety of secondary causes but may be idiopathic in approximately 50% of patients . 
 secondary causes may include head injury , subarachnoid hemorrhage , meningitis , and central nervous system tumor . here , we describe two extremely rare cases of supratentorial extraventricular space - occupying processes : meningioma and glioblastoma multiforme , which initially presented with nph .