“Location, Location, Location” A Systematic Approach to Pediatric Spinal Tumors “Location, Location, Location” A Systematic Approach to Pediatric Spinal Tumors Yun Sean Xie, Bundhit Tantiwongkosi, Wilson Altmeyer, Achint K Singh University of Texas Health Science Center Department of Radiology Department of Radiology eEdE#: 212

Financial Disclosure The Authors have no financial disclosure

Educational Objectives Review of a systematic approach to pediatric spinal tumors.

Introduction There are wide varieties of tumors involving the pediatric spine. In this presentation, we will discuss the relevant anatomy of the pediatric spine with emphasis on different compartments for appropriate localization of the tumor. Pediatric spinal tumors can be organized based on location into the bony compartment, epidural space, intradural extramedullary compartment, and intramedullary compartment as well as cauda equina and filum terminale. Each location has its own set of differentials, therefore it is important characterize the lesion first based on the location and then narrow the differentials based on history, patient’s demographics and imaging characteristics. Given the wide variety of tumors involving the pediatric spine, it is essential for a radiologist to have a systematic approach to narrow the differentials and provide useful guidance to the referring clinician. The imaging modalities of choice in pediatric spinal imaging are plain radiographs, CT and MR.

Anatomic Locations Epidural compartment Bony Compartment Intradural Extramedullary Intramedullary Filum Terminale and Cauda Equina

Imaging Algorithm for Localization of Spinal Tumors Step 1: Look at Spinal cord Expanded Not expanded/Compressed Step 2: Look at CSF (subarachnoid space) Expanded Not expanded/Compressed Intramedullary Intradural Extramedullary Extradural

Systematic Approach to Pediatric Spine Tumors Pediatric Spine Bony Compartment Aneurysmal bone cyst Giant cell tumor Osteoblastoma Ewing sarcoma Langerhans cell histiocytosis Chordoma Metastasis Epidural Space Epidural extension of Paraverteral or osseous tumors Intradural Extramedullary Meningioma Schwannoma Neurofibroma Epidermoid Intramedullary Ependymoma Astrocytoma Ganglioglioma Filum Terminale and Cauda Equina Myxopapillary ependymoma Filum lipoma

Systematic Approach to Pediatric Spine Tumors Pediatric Spine Bony Compartment Aneurysmal bone cyst Giant cell tumor Osteoblastoma Ewing sarcoma Langerhans cell histiocytosis Chordoma Metastasis Epidural Space Epidural extension of Paraverteral or osseous tumors. Intradural Extramedullary Meningioma Schwannoma Neurofibroma Epidermoid Intramedullary Ependymoma Astrocytoma Ganglioglioma Filum Terminale and Cauda Equina Myxopapillary ependymoma Filum lipoma

Aneurysmal Bone Cyst 10-30% of aneurysmal bone cysts (ABCs) occurs in the spine. 80% of patients present before the age of 20 and most commonly present with pain. Spinal ABCs typically start in the pedicle and expand into the vertebral body. About 30% of ABCs are primary lesions and the rest are secondary due to underlying lesions such as fibrous dysplasia, giant cell tumor, chondroblastoma or osteosarcoma. Imaging findings: Radiograph: Expansile remodeling of the bone with absent pedicle (absent pedicle sign)Radiograph: Expansile remodeling of the bone with absent pedicle (absent pedicle sign) CT: Balloon like expansile mass centered about the posterior elements extending into the vertebral bodyCT: Balloon like expansile mass centered about the posterior elements extending into the vertebral body MR:MR: Primary ABCs: lobulated multilocular cysts with variable signal intensity with fluid-fluid levelsPrimary ABCs: lobulated multilocular cysts with variable signal intensity with fluid-fluid levels Secondary ABCs: internal enchancing nodular component.Secondary ABCs: internal enchancing nodular component.

Aneurysmal Bone Cyst AP and lateral plain radiographs of the lumbar spine with expansile lytic lesion involving the L3 with expansion of left pedicle on the AP view

Giant Cell Tumor 3% of all giant cell tumors(GCT) occur in the spine % of GCT are benign and 5-10% can be malignant Overall more common in female (M:F of 1:3). This is especially true when it occurs in the spine. However malignant transformation is more common in men. Typically presents as insidious onset back pain, may present with pathologic fracture. GCT maybe locally aggressive in appearance with 5% of the cases presents with lung metastasis. Sarcomatous transformation can occur and is most frequent in post treatment patients. Imaging findings: Radiograph: Expansile lytic lesion of vertebral body with narrow zone of transitionRadiograph: Expansile lytic lesion of vertebral body with narrow zone of transition CT: Similar findings as radiograph but enhances on contrast images. Presents of fluid-fluid levels suggest secondary ABC.CT: Similar findings as radiograph but enhances on contrast images. Presents of fluid-fluid levels suggest secondary ABC. MR: Expansile enhancing mass with soft tissue component and narrow zone of transition. It appears low on T1 and intermediate to high signal intensity on T2MR: Expansile enhancing mass with soft tissue component and narrow zone of transition. It appears low on T1 and intermediate to high signal intensity on T2

Giant Cell Tumor Figure 1: Lateral plain film demonstrates a expansile lytic lesion involving the sacrum. Figure 2: Sagittal CT demonstrates an expansile lytic lesion involving the sacrum with large presacral soft tissue component. Figure 3: Sagittal T1-W post contrast MR demonstrates intense enhancement of the lesion about the sacrum

Osteoblastoma Prostaglandin-releasing benign osteoid forming tumor. Differentiated from osteoid osteoma by size (>1.5 cm). 40% of osteoblastoma occurs in the spine (posterior elements) and typically presents in the second decade of life. M:F of 2.5:1 Typically presents with dull pain that is worse at night with scoliosis. Neurogenic symptoms maybe present if large enough to cause nerve compression. Surgical excision is typically the treatment option. Imaging findings: CT: Well circumscribed expansile lesion with extension into the vertebral body, sclerotic rim and narrow zone of transition. It has variable amount of mineralization. The inflammatory response surround the tumor may present as ill defined sclerosis of surrounding bone or periosteal reaction.CT: Well circumscribed expansile lesion with extension into the vertebral body, sclerotic rim and narrow zone of transition. It has variable amount of mineralization. The inflammatory response surround the tumor may present as ill defined sclerosis of surrounding bone or periosteal reaction. MR: Low to isointense signal on T1 and T2 with internal foci of calcifications and adjacent bone marrow edema. The lesion typically shows avid enhancement.MR: Low to isointense signal on T1 and T2 with internal foci of calcifications and adjacent bone marrow edema. The lesion typically shows avid enhancement.

Osteoblastoma Figure 1 & 2: Sagittal and axial bone window images of the thoracic spine demonstrate an expansile lytic lesion involve the left pedicle. Figure 3: Axial image of the same lesion demonstrates a soft tissue component within the lesion. 1 23

Langerhans Cell Histiocytosis Also known as eosinophilic granuloma (EG). Peak incident rate between age of 1 to 3. Prevalence of 5 cases in 1 million children. It can present in any part of the skeletal system. Spine is the least commonly involved skeletal structure (6%). 50% of spinal involvement occurs in thoracic spine. Typically asymptomatic, but can present with pain due to pathologic fracture or expansion into the spinal canal or neuroforamen. Imaging findings : Best imaging feature is vertebral plana with sparing of the disc space. Radiograph: Lytic lesion with possible vertebral plana.Radiograph: Lytic lesion with possible vertebral plana. CT: Lytic vertebral lesion with enhancing soft tissue component that may extend into the epidural space.CT: Lytic vertebral lesion with enhancing soft tissue component that may extend into the epidural space. MR: T1 hypointense, T2 hyperintense with homogenous contrast enhancement.MR: T1 hypointense, T2 hyperintense with homogenous contrast enhancement.

Langerhans Cell Histiocytosis Figure 1: Lateral plain radiograph of the spine demonstrates vertebral plana involving the T10. Figure 2&3: Axial and sagittal CT of the cervical spine demonstrate a lytic lesion centered in the C1 left lateral mass. Figure 4&5: Axial post contrast T1 and sagittal T2 of the cervical spine demonstrates a T2 hyperintense enhancing lesion centered about the C1 left lateral mass.

Chordoma Malignant tumor originating from notochord remnants. Most common primary non lymphrproliferative malignancy of the spine. It can occur at any age but rare in pediatric population. 15% to 30% occurs in the vertebral bodies and 30-50% in the sacrum. Most common presentation in the spine is cord compression and radiculopathy. They are slow growing with 5 year survival rate of 60-80%. Recurrence is common. Imaging findings: CT: Well circumscribed expansile lytic lesion with irregular intratumoral calcifications.CT: Well circumscribed expansile lytic lesion with irregular intratumoral calcifications. MR: Low T1 and very high (similar to CSF) T2 signal intensity with variable enhancement.MR: Low T1 and very high (similar to CSF) T2 signal intensity with variable enhancement.

Chordoma 123 Figure 1, 2 & 3: Sagittal T1 (figure 1), T2 (figure 2) MR images of the cervical spine demonstrates a T1 isointense and T2 hyperintense lesion involving the clivus and C1 vertebral body with mass effect on the brain stem and extension into the anterior epidural space of C1. The sagittal T1 post gad (figure 3) demonstrates heterogeneous enhancement of the lesion.

Ewing Sarcoma Second most common primary malignancy of bone of childhood. 90% of patients present before age of 20. Most common clinical presentation is localized pain, fever, elevated ESR and leukocytosis. Spinal Ewing sarcoma accounts for 5% of all Ewing tumors with sacrum being the most common site. Systemic chemotherapy is the mainstay of treatment. Most important prognostic factor is presence of metastasis at time of presentation. Imaging findings: Radiograph: Lesion centered in the vertebral body with permeative destruction of the bone and wide zone of transition. May involve adjacent vertebral body.Radiograph: Lesion centered in the vertebral body with permeative destruction of the bone and wide zone of transition. May involve adjacent vertebral body. CT: Permeative vertebral body mass with large soft tissue component that demonstrates heterogeneous enhancement.CT: Permeative vertebral body mass with large soft tissue component that demonstrates heterogeneous enhancement. MR: T1 low and T2 isointense soft tissue lesion centered in the vertebral body and heterogeneous post- contrast enhancement.MR: T1 low and T2 isointense soft tissue lesion centered in the vertebral body and heterogeneous post- contrast enhancement.

Ewing Sarcoma 1 23 Figure 1&2: Axial and sagittal CT demonstrate a soft tissue mass involving the sacrum with osseous destruction. Figure 3: Sagittal T2 of the lumbar spine demonstrates a T2 isointense soft tissue mass centered about the sacrum.

Systematic Approach to Pediatric Spine Tumors Pediatric Spine Bony Compartment Aneurysmal bone cyst Giant cell tumor Osteoblastoma Ewing sarcoma Langerhans cell histiocytosis Chordoma Epidural Space Epidural extension of paraverteral or osseous tumors Intradural Extramedullary Meningioma Schwannoma Neurofibroma Epidermoid Intramedullary Ependymoma Astrocytoma Hemangioblast oma Ganglioglioma Filum Terminale and Cauda Equina Myxopapillary ependymoma Filum lipoma

Epidural Space Figure 1: Bone window CT of the thoracic spine demonstrates a “Corduroy Sign” appearance of the T Spine vertebral body consistent with osseous hemangioma. Figure 2, 3 & 4: Sagittal T1 (figure 2), SPAIR (figure 3) and Post gad T1 (figure 4) demonstrate an atypical hemangioma with extension into the anterior and posterior epidural spaces (arrows).

Systematic Approach to Pediatric Spine Tumors Pediatric Spine Bony Compartment Aneurysmal bone cyst Giant cell tumor Osteoblastoma Ewing sarcoma Langerhans cell histiocytosis Chordoma Epidural Space Epidural extension of Paraverteral or osseous tumors. Intradural Extramedullary Meningioma Schwannoma Neurofibroma Epidermoid Intramedullary Ependymoma Astrocytoma Ganglioglioma Filum Terminale and Cauda Equina Myxopapillary ependymoma Filum lipoma

Meningioma Slow growing benign tumor from dura mater. Thoracic > cervical > lumbar in location. 2 nd most common intradural extramedullary primary tumor. Most are sporadic and solitary unless associated with NF2. Female to male ratio of 4:1. Most commonly presents with sensory and motor deficits. Peak incidence is in 5 th -6 th decade of life. When presenting under age of 50, it is commonly associated with genetic syndrome particularly in pediatric patients. Surgical resection is treatment of choice. Imaging Findings: CT: NECT has similar attenuation as the spinal cord with CECT demonstrates homogeneous enhancement. Calcifications present in 1-5% of casesCT: NECT has similar attenuation as the spinal cord with CECT demonstrates homogeneous enhancement. Calcifications present in 1-5% of cases MR: T1 isointense, T2 mainly isointense but can present as T2 hyper or hypointense lesion depend on calcification or cellularity. Homogenous post contrast enhancement. Dural tail may not be present in the spine.MR: T1 isointense, T2 mainly isointense but can present as T2 hyper or hypointense lesion depend on calcification or cellularity. Homogenous post contrast enhancement. Dural tail may not be present in the spine.

Meningioma Figure 1 & 2: Sagittal T2 and axial T2 images of the cervical spine demonstrate a T2 heterogeneous intradural extramedullary lesion centered about C5 level with significant mass effect on the spinal cord. The T2 hypointense signal within the mass my represent calcifications Figure 3: T1 post contrast axial image shows the same lesion with homogeneous enhancement

Schwannoma Most common intradural extramedullary spinal tumors. Most commonly located in the cervical and lumbar region. Typical clinical presentation is pain, sensory and motor dysfunction. It may be associated with NF2. Imaging Findings: CT:CT:  NECT shows a spherical or elongated (dumbbell shaped) mass in the paravertebral region and spinal canal. Most common in ventral location.  CECT shows post contrast enhancement. MR:MR:  T1 isointense to the cord and T2 isointense to hyperintense signal depends on the cystic component. It shows heterogeneous post contrast enhancement.

Schwannoma Figure 1: Sagittal T2 images of the cervical spine in patient with known history of NF2 demonstrates multiple T2 isointense to mildly hyperintense nerve sheath tumors involving the cervical spine nerve roots with expansion of the neuroforamina. Figure 2 & 3: Sagittal T1 (figure 2) and post gad T1 (figure 3) images demonstrate enhancement of the multiple schwannomas involving the cervical spine nerve roots

Neurofibroma May be associated with neurofibromatosis type I or von Recklinghausen disease Autosomal dominant disease presents with multiple nerve sheath tumors, plexiform neurofibroma, dural ectasia, kyphoscoliosis, cutaneous lesions and brain lesions. First clinical clue incudes café au lait spots, kyphoscoliosis and cutaneous neurofibromas. 3 types of NF1 are described: localized, diffuse and plexiform. Imaging Findings: Radiograph: kyphoscoliosis with posterior scalloping of the vertebral bodyRadiograph: kyphoscoliosis with posterior scalloping of the vertebral body CT: Fusiform or focal nerve root enlargement with dural ectasia.CT: Fusiform or focal nerve root enlargement with dural ectasia. MR: T1 isointense, T2 hyperintense lesions with mild post contrast enhancement. Nerve root neurofibroma with “Target sign” peripheral T2 hyperintensity with internal low T2 signal.MR: T1 isointense, T2 hyperintense lesions with mild post contrast enhancement. Nerve root neurofibroma with “Target sign” peripheral T2 hyperintensity with internal low T2 signal.

Neurofibroma Figure 1: Axial T1 post gad image demonstrates a homogenously enhancing intradural extramedullary lesion with mass effect on the adjacent spinal cord. This patient has a history of NF1 with multiple other small peripheral neurofibromas. Figure 2: Sagittal T2 images of the lumbar spine demonstrates dural ectasia with posterior scalloping of lumbosacral vertebrae. 12

Epidermoid Cyst Benign spinal cystic mass derived from epidermal elements. 10% of spinal lesion in pediatric patients less than age of 15. It can be intramedullary(40%) or extramedullary (60%). Congenital epidermoid cyst (60%) can occur anywhere along the spine. But acquired (40%) lesion usually occurs at cauda equina. It can be associated with dermal sinus tracts and vertebral abnormalities. Large epidermoid cysts can cause radiculopathy due to compression of the spinal cord. Surgical resection is treatment of choice. Imaging Findings: CT: Well circumscribed mass with CSF attenuation without significant enhancement.CT: Well circumscribed mass with CSF attenuation without significant enhancement. MR: T1 isointense, T2 hyperintense lesions without significant enhancement. Restricted diffusion is hallmark on MRI.MR: T1 isointense, T2 hyperintense lesions without significant enhancement. Restricted diffusion is hallmark on MRI.

Epidermoid Cyst Figure 1, 2 & 3: Sagittal T1 (figure1), T2 (figure 2) and DWI (figure 3) images demonstrate a T1 hypointense and T2 isointense to CSF intradural extramedullary lesion that shows restricted diffusion on DWI consistent with an epidemoid cyst. Please note the low lying tethered cord (red arrow). 1 23

Systematic Approach to Pediatric Spine Tumors Pediatric Spine Bony Compartment Aneurysmal bone cyst Giant cell tumor Osteoblastoma Ewing sarcoma Langerhans cell histiocytosis Chordoma Epidural Space Epidural extension of Paraverteral or osseous tumors. Intradural Extramedullary Meningioma Schwannoma Neurofibroma Epidermoid Intramedullary Ependymoma Astrocytoma Ganglioglioma Filum Terminale and Cauda Equina Myxopapillary ependymoma Filum lipoma

Ependymoma Originated from ependymal cells of central canal WHO grade II tumor. Anaplastic astrocytoma (WHO III) rare. It may be associated with NF2. 4 subtypes: cellular, mayxopapillary, clear cell and tanycytic. 2 nd most common primary intradural intramedullary tumor of spine in pediatric patients. Most common clinical presentation is pain. Complete surgical resection is achievable in 50% of cases. Imaging Findings: CT: Enlargement of spinal canal with post contrast enhancement.CT: Enlargement of spinal canal with post contrast enhancement. MR: Enlargement of spinal canal that is T1 isointense and T2 hyperintense signal with enhancement on post contrast images. Cystic component is present in 22% of the cases and syringohydromeyelia in 9-50% of the cases.MR: Enlargement of spinal canal that is T1 isointense and T2 hyperintense signal with enhancement on post contrast images. Cystic component is present in 22% of the cases and syringohydromeyelia in 9-50% of the cases.

Ependymoma Figure 1 & 2: Axial T2 and post gad T1 images of thoracic spine demonstrate an intradural intramedullary lesion involving the thoracic spinal cord with cord enlargement. Figure 3 & 4: Sagittal T2 and Post Gad T1 images of the thoracic spine demonstrates an enhancing T2 hyperintense thoracic cord lesion with cord expansion. Multiple enhancing metastatic lesions are seen as well.

Astrocytoma 2 nd most common intramedullary tumor of the spine. Most commonly located in the cervical spinal cord. 60% of all pediatric intramedullary tumors. 85% of cases are low grade such as pilocytic astrocytoma or ganglioglioma. 15% are high grade such as anaplastic astrocytoma. Most cases in pediatric population are WHO grade I or II tumors. Most common presenting symptom is slow onset of myelopathy. Imaging Findings: CT: Enlargement of the spinal cordCT: Enlargement of the spinal cord MR: Spinal cord expansion (< 4 contiguous segments) with presence of cystic component and syrinx. May have hemorrhagic product. The majority will enhance on the post contrast images.MR: Spinal cord expansion (< 4 contiguous segments) with presence of cystic component and syrinx. May have hemorrhagic product. The majority will enhance on the post contrast images.

Pilocytic astrocytoma 1 23 Figure 1: Axial T2 of thoracolumbar spine demonstrate an intradural intramedullary mass with cystic component involving the filum terminale. Figure 2 & 3: Sagittal T2 and post gad T1 images demonstrate an enhancing cystic mass involving the filum terminale.

Ganglioglioma Figure 1 & 3: Axial T1 pre (figure 1) and post gad (figure 3) of the thoracic spine demonstrate a minimally enhancing T1 isointense intramedullary mass involving the thoracic spinal cord with cord enlargement. Figure 2 & 4: Axial and sagittal T2 images demonstrate a T2 hyperintense intramedullary mass involving the thoracic spinal cord with cord enlargement.

Systematic Approach to Pediatric Spine Tumors Pediatric Spine Bony Compartment Aneurysmal bone cyst Giant cell tumor Osteoblastoma Ewing sarcoma Langerhans cell histiocytosis Chordoma Epidural Space Epidural extension of Paraverteral or osseous tumors. Intradural Extramedullary Meningioma Schwannoma Neurofibroma Epidermoid Intramedullary Ependymoma Astrocytoma Ganglioglioma Filum Terminale and Cauda Equina Myxopapillary ependymoma Filum lipoma

Myxopapillary Ependymoma Subtype of ependymoma occurs exclusively at the conus medullary and filum terminale Slight male predominance. WHO grade I tumors. Most common presentation is radiculopathy, bladder or bowel dysfunction. May present as subarachnoid hemorrhage in some cases. Surgical resection is treatment of choice. Imaging Findings: CT: Isointense intradural massCT: Isointense intradural mass MR: T1 isointense, T2 hyperintese lesion with peripheral hypointensity due to hemosiderin. Intense heterogeneous enhancement on most contrast images.MR: T1 isointense, T2 hyperintese lesion with peripheral hypointensity due to hemosiderin. Intense heterogeneous enhancement on most contrast images.

Myxopapillary Ependymoma Imaging pediatric spine tumors. Appl Radiol. By Karuna V. Shekdar, MD. and Erin Simon Schwartz, MD. November 05, Figure 1 & 2: Sagittal and Axial T2 images of the lumbar spine demonstrate a hyperintense lesion involving the filum terminale. Figure 3: Sagittal T1 post gad demonstrates homogeneous enhancement of the T2 hyperintense filum terminale lesion.

Filum Terminale Fibrolipoma Also known as lipoma of the filum terminale. Usually incidental but can be associated with tethered cord if thicker than 2 mm. Prevalence of 5%. Majority of the cases are asymptomatic unless associated with tethered cord or spinal dysraphism. No treatment required for asymptomatic patients and surgical resection for patients with tethered cord. Imaging Findings: CT: May see fat density distal to the conus.CT: May see fat density distal to the conus. MR: T1 hyperintense and T2 hyperintense with loss of signal on fat saturation images. No evidence of enhancement.MR: T1 hyperintense and T2 hyperintense with loss of signal on fat saturation images. No evidence of enhancement.

Filum Terminale Fibrolipoma Figure 1 & 2: Axial T1 and sagittal T1 images of the lumbar spine demonstrate a T1 hyperintense lesion involving the filum terminale. Figure 3 & 4: Sagittal T2 and sagittal T2 fat saturation images of the lumbar spine demonstrate a T2 hyperintense lesion involving the filum terminale with loss of signal on the fat saturation sequence consistent with a lipoma of the filum terminale. No tethered cord

Conclusion There are a wide variety of pediatric spinal tumors, therefore it is essential for a radiologist to have a systematic approach to narrow the differential and provide useful guidance to the referring clinician. The first step in approach to any pediatric spinal tumor is to identify its location in the different compartments of the pediatric spine using the described 2 step algorithmic approach. This step is crucial and tremendously helpful in narrowing down the differential.

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