a malignant peripheral nerve sheath tumor ( mpnst ) is a sarcoma that arises from peripheral nerves or cells of the associated nerve sheath ( schwann cells , perineural cells , fibroblasts ) . the term " mpnst " has substituted previously used terms such as malignant schwannoma , neurofibrosarcoma , and neurogenic sarcoma1,2 ) . the mpnsts comprise approximately 5% to 10% of all soft tissue tumors and have an incidence of 0.001% in the general population and the etiology is unknown . however , more than half of mpnst cases develop in patients with neurofibromatosis type-1 ( nf-1 ) and there is a higher incidence in patients that have undergone prior radiotherapy1,2,5,8,13 ) . mpnsts are most likely to metastasize to the lungs , followed by the bone and finally the pleura , but , spinal cord and brain metastasis is very rare in non - nf-1 mpnst3,7 ) . the authors report a very rare case of spinal cord and brain metastasis of mpnst in the lumbar spine that occurred in a 18-year - old man without nf . an 18-year - old man presented initially with a 6-month history of low back pain that worsened over time . one month prior to admission , the patient developed radiating pain to his anterior thigh . neither caf au lait spots nor neurofibromas were seen and his family history was absent of nf-1 . the neurologic examination showed normal motor power in his lower extremities . magnetic resonance imaging ( mri ) showed a paraspinal mass that extended from the central space of l2 to the right psoas muscle through right l2 - 3 foraminal space . it was an asymmetrical dumbbell shaped mass and the thecal sac was displaced left by the mass . the mass showed iso - signal intensity on t1-weighted images and mixed signal intensity on t2-weighted images . a paramedian incision was made from the l1 to l4 and we exposed the right l2 and l3 lamina with transverse process . right l2 hemilaminectomy was performed using a high speed drill and kerrison rongeur to expose the thecal sac . the margin of mass was relatively distinct from neural tissue , thus gross total resection was possible under microscopic view . to remove the mass extended to the psoas muscle , the right transverse process of l2 and l3 was resected and the mass was visible . after the operation , his symptom had improved . however , a few days later , his confirmed pathologic report was presented as mpnst ( fig . the contrast - enhanced mri was followed at 1 month after the operation and revealed a total removal of tumor ( fig . however , the patient declined the external beam radiation due to the fear of potential radiation risk . spine and brain mri showed that the tumor recurrence with leptomeningeal , multiple spinal cord and brain metastases ( fig . 4 ) . complete surgical clearance of the tumor was not technically feasible , owing to the multiple metastases . therefore , the patient was referred for adjuvant chemotherapy . in addition , intrathecal chemotherapy was performed . after 4 months of chemotherapy , he was referred to the hospice hospital and died within a month . an 18-year - old man presented initially with a 6-month history of low back pain that worsened over time . one month prior to admission , the patient developed radiating pain to his anterior thigh . neither caf au lait spots nor neurofibromas were seen and his family history was absent of nf-1 . the neurologic examination showed normal motor power in his lower extremities . magnetic resonance imaging ( mri ) showed a paraspinal mass that extended from the central space of l2 to the right psoas muscle through right l2 - 3 foraminal space . it was an asymmetrical dumbbell shaped mass and the thecal sac was displaced left by the mass . the mass showed iso - signal intensity on t1-weighted images and mixed signal intensity on t2-weighted images . a paramedian incision was made from the l1 to l4 and we exposed the right l2 and l3 lamina with transverse process . right l2 hemilaminectomy was performed using a high speed drill and kerrison rongeur to expose the thecal sac . for removal of intradural portion the margin of mass was relatively distinct from neural tissue , thus gross total resection was possible under microscopic view . to remove the mass extended to the psoas muscle , the right transverse process of l2 and l3 was resected and the mass was visible . after the operation , his symptom had improved . however , a few days later , his confirmed pathologic report was presented as mpnst ( fig . the contrast - enhanced mri was followed at 1 month after the operation and revealed a total removal of tumor ( fig . however , the patient declined the external beam radiation due to the fear of potential radiation risk . spine and brain mri showed that the tumor recurrence with leptomeningeal , multiple spinal cord and brain metastases ( fig . 4 ) . complete surgical clearance of the tumor was not technically feasible , owing to the multiple metastases . in addition , intrathecal chemotherapy was performed . however , no significant effect was observed and the patient 's condition deteriorated gradually . after 4 months of chemotherapy , he was referred to the hospice hospital and died within a month . non - nf-1 mpnsts are very rare and the occurrence of mpnsts occurring in adolescents is very rare . mpnsts generally occur in adulthood typically between the ages of 20 and 50 years of age . approximately 10 - 20% of cases have been reported to occur in the first 2 decades of life , with occasional cases involving infants as young as 11 months of age5,6 ) . hruban et al . described 43 patients with mpnst and of these patients , 28 ( 65% ) had distant metastasis3 ) . sites of metastasis included the lungs ( 22 cases ) , bone ( 9 cases ) , pleura ( 6 cases ) , retroperitoneum ( 4 cases ) , diaphragm ( 3 cases ) , inguinal lymph nodes ( 2 cases ) , liver ( 2 cases ) , chest wall ( 2 cases ) , soft tissue ( 2 cases ) , pulmonary hilum , pericardium , thyroid gland , and adrenal gland ( 1 case each ) . described 11 distant metastasises in 54 patients with mpnst that included metastases to lymph nodes , pleura , lung , liver , adrenal gland , leptomeninges and brain7 ) . william et al.4 ) reported a non - nf-1 mpnst case of metastasis to the spinal cord4 ) . our case showed that leptomeningeal , spinal cord and brain metastasis of non - nf-1 mpnst for relatively short period after tumor removal in young male patient , reflecting aggressive nature of this malignancy . the outcome with respect to both local recurrence and distant metastasis largely depends on grade of surgical excision . radiation therapy combined with wide surgical excision offers statistical significant reduction in the rates of local disease recurrence . however , it has not had a meaningful reduction in either rate of distant metastasis or overall survival15 ) . benefit of chemotherapy is unproven and its application is limited to high grade metastatic disease3 ) . the italian and german soft tissue sarcoma cooperative group reported an overall pediatric response rate of 45% , with the highest response noted within the ifosfamide group9,11,12 ) . the recurrence rate for mpnsts has been reported to range from 40 - 68%7,10,14 ) . the 5-year survival rate has been reported at 16 - 52% and a favorable prognosis has been related with complete surgical excision of the tumors that are sized less than 5 cm7,10 ) . historically , mpnsts have been difficult tumors to treat due to their inherently aggressive nature and dismal prognosis . our patient underwent complete surgical excision , but the patient was not treated with radiotherapy . follow - up images revealed multiple spinal cord and brain metastases . the patient was managed with chemotherapy , but expired several months later . despite complete surgical excision , we reported a case of mpnst that had metastasized to the brain and spinal cord . because the mpnst showed both rapid and aggressive progression , patients should be followed carefully to identify local recurrence or metastasis and be mandatory an adjuvant radiotherapy .
a malignant peripheral nerve sheath tumor ( mpnst ) is a type of sarcoma that arises from peripheral nerves or cells of the associated nerve sheath . 
 this tumor most commonly metastasizes to the lung and metastases to the spinal cord and brain are very rare . 
 we describe a case of young patient with spinal cord and brain metastases resulting from mpnst . 
 an 18-year - old man presented with a 6-month history of low back pain and radiating pain to his anterior thigh . magnetic resonance imaging showed a paraspinal mass that extended from the central space of l2 to right psoas muscle through the right l2 - 3 foraminal space . 
 the patient underwent surgery and the result of the histopathologic study was diagnostic for mpnst . 
 six months after surgery , follow - up images revealed multiple spinal cord and brain metastases . 
 the patient was managed with chemotherapy , but died several months later . despite complete surgical excision , 
 the mpnst progressed rapidly and aggressively . 
 thus , patients with mpnst should be followed carefully to identify local recurrence or metastasis as early as possible .