|Year : 2012 | Volume
| Issue : 2 | Page : 126-128
Giant lumbosacral schwannoma in a child
Rashim Kataria, Dhruba Jyoti Kurmi, Jayanti Mehta, Virendra Deo Sinha
Department of Neurosurgery, SMS Medical College, Jaipur (Rajasthan), India
|Date of Web Publication||17-Oct-2012|
Assistant Professor (Neurosurgery), 53, Mauji Colony, Malviya Nagar, Jaipur (Rajasthan)
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Small spinal intradural extramedullary schwannoma are a common occurrence in the middle aged. However, giant schwannoma in pediatric age group is rare. We report one such case of giant extradural lumbosacral schwannoma in an 8-year-old child. Clinical features, histopathology and management of giant schwannoma is discussed and the present literature reviewed.
Keywords: Extramedullary mass, giant schwannoma, spinal tumors
|How to cite this article:|
Kataria R, Kurmi DJ, Mehta J, Sinha VD. Giant lumbosacral schwannoma in a child. J Pediatr Neurosci 2012;7:126-8
| Introduction|| |
Schwannoma or neurilemmomas are firm, encapsulated neoplasms composed principally of neoplastic Schwann cells from the spinal nerve root sheath. These mostly occur sporadically and solitary, but they may also be associated with neurofibromatosis-2 (NF-2), and less commonly with neurofibromatosis-1 (NF-1). Occurrence of giant spinal schwannoma in pediatric age group is rare. These are usually small and complete excision with good neurological recovery is a rule rather than exception. However, schwannoma in lower lumbar and sacral regions can enlarge significantly and can further extend into the paravertebral space. Giant schwannoma in contrast to their smaller counterparts pose difficulty in complete excision because of their paravertebral extension. Moreover, they engulf spinal nerves as they enlarge in size hence making complete excision difficult. A multistage, multidisciplinary approach is often required for removal of these tumors. We report a case of giant extradural lumbosacral schwannoma in an 8-year-old male without neurofibromatosis.
| Case Report|| |
An 8-year-old male child presented with complaints of low backache for 1 year. Neurological examination of the patient did not reveal any abnormality except for local tenderness at L4 and L5 spinous process. Plain radiographs of the lumbosacral spine [Figure 1] revealed increased interpedicular distance at L4, L5, S1 levels, widening of the L4-5, L5-S1 neural foramina and scalloping of the posterior surface of L4 and L5 vertebral body. Magnetic resonance imaging (MRI) of the lumbosacral spine [Figure 2]a showed an extradural mass against L4 to S2 vertebral bodies with significant right paravertebral component. The mass was hypo to iso intense on T1-weighted images and hyper intense on T2-weighted images. There was heterogeneous enhancement of the mass after contrast. Patient underwent L3 to S2 laminectomy with subtotal excision (complete excision from within the canal and partial excision of the paravertebral part) of the mass from the posterior approach only [Figure 2]b. The mass was firm, encapsulated, moderately vascular, and entirely extradural. Instrumentation was not done considering the young age of the patient. Patient was relieved of pain after the surgery. He was on bed rest for 6 weeks after the surgery.
|Figure 1: Plain radiographs of the lumbosacral spine showing increased interpedicular distance at L4, L5, S1 levels, widening of the L4-5, L5-S1 neural foramina and scalloping of the posterior surface of L4 and L5 vertebral body|
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|Figure 2: MRI of the lumbosacral spine (a) showed an extradural mass against L4 to S2 vertebral bodies with significant right paravertebral component. Postoperative MRI (b) showing surgical cavity after the excision of the mass|
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Histopathology examination (HPE) [Figure 3]a and b of the tumor reveals Antoni A and Antoni B areas. Antoni A tissue is cellular and consists of monomorphic spindle shaped Schwann cells with poorly defined eosinophilic cytoplasm and spindle shaped basophilic nuclei. Pallisading of nuclei and verocay body were seen. Antoni B area is hypo cellular characterized by the presence of Schwann cells suspended in copious myxoid matrix with microcyst formation.
|Figure 3: (a) Antoni A tissue is cellular (white arrow) with nuclear palisading. Antoni B tissue (black arrow) is loose with microcyst formation. (b) Typical verocay body (hollow arrow)|
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| Discussion|| |
Spinal schwannoma account for about 25% of spinal cord tumors in adults. Seppälä et al. reported an incidence of about 0.3 and 0.4 cases per 100 000 persons per year.  The exact size when to label a schwannoma as giant is not described. Sridhar et al. classified giant schwannoma as those that extend over more than two vertebral levels (type II), those that have extra spinal extension of more than 2.5 cm (giant dumbbell, type IV) and those lesions that erode vertebral bodies and extend posterior and laterally into the myo-fascial planes (giant invasive tumors, type V). Schwannoma of the lower lumbar and sacral regions, because of the wide canal available at these locations and relatively mobile nerve roots can enlarge significantly and can extend vertically and in the paravertebral regions.
The incidence of giant schwannoma in pediatric age group is rare. This can be supported by the fact that in a study of 118 cases of spinal dumbbell tumors, only one dumbbell schwannoma was seen in the pediatric age group. 
Initial symptoms depend upon the location of the tumor and are due to irritation of the involved sensory nerve. Giant schwannoma commonly present with local pain and neurologic deficit develops late.
Giant schwannoma, because of their growth in all directions, may extend:
- Vertically to involve multiple vertebral levels,
- Anterolaterally into extra spinal space via the foramen which they may erode and widen,
- Posteriorly, thinning and attenuation of dura and posterior elements and occasionally may extend posterior myo-fascial planes, and
- Anteriorly, erode the vertebral bodies to varying extents.
No radiographic findings are pathognomic for intraspinal schwannoma. Plain radiographs may reveal widening of the neural foramen and the spinal canal, erosion of the pedicle, and scalloping of the adjacent vertebral body. On MRI, signal characteristics of a typical schwannoma are:
- T1W: Iso to hypo intense to that of spinal cord
- T2W: Typically hyper intense and often heterogeneous in pattern of intensity
- T1+Contrast: Shows heterogeneous enhancement with evidence of hemorrhage, calcification, or cyst formation.
MRI is the gold standard investigation delineating the extent of giant schwannoma and hence deciding the approach for surgery. 3-Dimensional computed tomography (3D CT) can reveal positional relationship between tumor and iliac arteries in cases of giant sacral schwannoma.  When the mass is predominantly involving the sacrum it is important to consider other benign (osteoblastoma, aneurysmal bone cyst, and giant cell tumor) and malignant(metastatic carcinoma, myeloma, chordoma, and chondrosarcoma) sacral tumors in the differential diagnosis.
Treatment of giant schwannoma is aimed at radical resection of the tumor. It consists of preoperative planning for the approach to be taken up for surgery. In most of the cases of dumbbell tumors conventional posterior approach alone suffice the complete removal of the mass as in these cases the neural foramen is usually considerably widened. If the mass is invasive and if the lateral paravertebral extension is very large, a staged or single combined posterior and anterolateral approach can be used. In cases where intra spinal component is small as compared with the lateral portion, complete excision can be done through the anterolateral approach. Giant invasive schwannoma erode the posterior surface of the vertebral bodies. Laminectomy with removal of more than one facet can lead to unstable spine. Stability of the spine has to be ensured by instrumentation after removal of the tumor. However, as our patient was a child we did not do instrumentation.  Although schwannoma arises from the nerve tissue, only in 50% cases a direct relationship with a nerve is found. It is usually possible to preserve some fascicles of the nerve root, although sometimes section of the entire nerve root is required, usually in invasive giant varieties. Kim et al. reported that sacrificing an involved nerve root does not cause increase in the neurological deficits as the involved nerve root is nonfunctional.
The differential diagnosis of paraspinal lumbar masses includes a variety of lesions. Schwannoma, neurofibroma, meningioma, ependymoma, sarcoma, ganglioneuroma, connective and bone tissue, abscess, herniated disc, hematoma, spinal arteriovenous malformation (AVM), and spinal aneurysm, as well as metastatic disease should be under consideration.
| Conclusion|| |
Giant schwannoma are rare in children, complete excision of the tumor should be the goal of surgery. We recommend instrumentation only if the spine is unstable otherwise a wait and watch protocol be followed as spontaneous remodeling of the scalloped vertebral bodies is well known.
| References|| |
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|2.||Sridhar K, Ramamurthi R, Vasudevan MC, Ramamurthi B. Giant invasive spinal schwannoma: Definition and surgical management. J Neurosurg 2001;94:210-5. |
|3.||Ozawa H, Kokubun S, Aizawa T, Hoshikawa T, Kawahara C. Spinal dumbbell tumors: An analysis of a series of 118 cases. J Neurosurg Spine 2007;7:587-93. |
|4.||Satake K, Matsuyama Y, Yoshihara H, Yanase M, Miura Y. Three-dimensional images for surgical plan of giant sacral schwannoma. Spinal Cord 2004;42:368-70. |
|5.||Piera JB, Durand J, Pannier S, Guiot G, Grossiord A. [10 cases of giant lumbo-sacral neurinoma]. Ann Med Interne (Paris) 1975;126:316-30. |
|6.||Kim P, Ebersold MJ, Onofrio BM, Quast LM. Surgery of spinal nerve schwannoma. Risk of neurological deficit after resection of involved nerve root. J Neurosurg 1989;71:810-4. |
[Figure 1], [Figure 2], [Figure 3]