|Year : 2019 | Volume
| Issue : 2 | Page : 158-162
Multiple spinal schwannomas in absence of neurofibromatosis (Schwannomatosis) – A rare condition: Review with case report
Sandeep Bhardwaj, Kunj Bihari Saraswat, Amit Pratap Singh Deora, Ashok Gupta
Department of Neurosurgery, SMS Hospital, Jaipur, Rajasthan, India
|Date of Web Publication||23-Jul-2019|
Dr. Sandeep Bhardwaj
Room No. F 13, Resident Doctors Hostel, SMS Hospital, Jaipur, Rajasthan
Source of Support: None, Conflict of Interest: None
Schwannomas are benign, slow-growing tumors originating from sensory rootlets. Schwannomatosis is a distinct clinical syndrome characterized by the presence of multiple schwannomas in the spine with the absence of typical features suggestive of either neurofibromatosis 1 (NF1) and neurofibromatosis 2 (NF2). It is essential to name schwannomatosis as a distinct syndrome on the basis of genetic and molecular studies. Management in schwannomatosis is surgical removal if symptomatic, and if asymptomatic it is better to follow-up with regular screening. The author reports here a rare case of a 33-year-old male patient, who had a history of being operated for dorsal spine schwannoma at D6 level 7 years back. Now, after 7 years, the patient presented with back pain, moderate to severe, associated with difficulty in walking. After proper history, clinical and radiological evaluation the patient was found to be having multiple lesions at D12 and L3 level with no family history, and on histopathology, both lesions were found to be schwannomas. Hence, this case was diagnosed as a case of multiple schwannomas without any features suggestive of either NF1 or NF2 (schwannomatosis). Regular follow-up is very essential in every case suggestive of schwannoma, as new multiple lesions can develop at any time, after years as discussed in our case.
Keywords: Laminectomy, neurofibromatosis 1, neurofibromatosis 2, schwannomatosis, spinal schwannomas, spine
|How to cite this article:|
Bhardwaj S, Saraswat KB, Deora AP, Gupta A. Multiple spinal schwannomas in absence of neurofibromatosis (Schwannomatosis) – A rare condition: Review with case report. Indian Spine J 2019;2:158-62
|How to cite this URL:|
Bhardwaj S, Saraswat KB, Deora AP, Gupta A. Multiple spinal schwannomas in absence of neurofibromatosis (Schwannomatosis) – A rare condition: Review with case report. Indian Spine J [serial online] 2019 [cited 2020 Aug 7];2:158-62. Available from: http://www.isjonline.com/text.asp?2019/2/2/158/263273
| Introduction|| |
Schwannomas are the most common nerve sheath tumors originating in Schwann cells. Most of the schwannomas are single sporadic benign neoplasms. Both schwannomas and neurofibromatosis originate from insulated covering of nerve rootlets. Schwannomas are slow-growing, homogenous tumors which originate from Schwann cells. They develop on the outside of the nerve but may push it aside or against adjacent structures causing damage. They represent about one-third of all benign primary spinal tumors.
Neurofibromas are heterogenous tumors which have the tendency to displace individual nerve fibers and infiltrate nerves. The presence of multiple schwannomas in a single patient suggests tumorigenesis and possible association with one of the syndromes, most commonly with neurofibromatosis 2 (NF2). The patients with features suggestive of schwannomatosis can have multiple schwannomas on various cranial, spinal, and peripheral nerves; however, these do not develop vestibular schwannomas. They do not develop other tumors such as meningiomas, ependymomas, or astrocytoma.,,,,, The patients with schwannomatosis usually present with pain; however, NF2 presents with neurological deficit., The molecular and genetic analysis also suggests that schwannomatosis is a distinct clinical and genetic syndrome.,
| Case Report|| |
A 33-year-old male patient had a history of being operated for D6 level, intradural extramedullary mass in 2010 about 7 years back [Figure 1] and [Figure 2]. Histopathology at that time was reported as schwannoma. The patient was almost asymptomatic for the last 7 years. After a gap of 7 years, he again presented with complaints of low back pain for 6 months, radicular pain in both legs for similar duration, and difficulty in walking for 2 months. The patient was almost asymptomatic for the last 7 years and had no follow-up in these years.
|Figure 1: Preoperative magnetic resonance imaging scan in 2010 with lesion at D6 level|
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|Figure 2: Preoperative axial MRI spine image, lesion at D6 level in 2010|
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The patient was inquired about any family history suggestive of neurofibromatosis or schwannomatosis in first-degree relatives, but no significant family history was found. On neurological examination, the patient had low back pain with paresthesias in both lower extremities. Straight leg raising test was negative, sphincter function was normal and increased reflexes in both lower limbs were present. No other neurological deficit was present, including cranial nerves, especially eighth cranial nerve, with no stigmata suggestive of neurofibromatosis.
On radiological investigations in 2017, magnetic resonance imaging (MRI) of dorsolumbar spine showed the presence of two mass lesions being hypointense on T1 and hyperintense on T2 at levels D12 and L3–L4 [Figure 3]. He was further investigated with MRI cervical spine and screening MRI whole spine which revealed similar findings. MRI brain was performed to rule out NF2. No visible mass lesion was identified and was reported grossly normal [Figure 4]. The patient was planned for operative intervention because of interference with his activities of daily living and associated pain. The removal of both lesions was performed. D12 and L3 laminectomy was performed with complete microscopic excision of masses as in intraoperative pictures [Figure 5].
|Figure 3: Preoperative MRI spine T2WI (sagittal) suggestive of two mass lesions at D12 and L3–L4 levels (in 2017)|
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|Figure 5: Intraoperative picture depicting two mass lesions at D12 and L3–L4 levels|
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A biopsy was sent separately for both mass lesions. On histopathological examination both lesions were found to be schwannomas [Figure 6] and [Figure 7]. Postoperatively, the patient showed progressive recovery for both back and leg pain. The patient had no postoperative surgical or neurological complication and made progressive recovery. Postoperative MRI performed showed complete excision of both masses [Figure 8]. The patient at one month followup was completely pain free and was relieved of his walking difficulty. The genetic and molecular analysis was recommended to the patient; however, the patient refused due to financial constraints.
|Figure 6: Histopathological image of lesion at D12 level suggestive of schwannoma|
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|Figure 7: Histopathological image of lesion at L3–L4 level suggestive of schwannoma|
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Hence, this patient had three lesions at three different sites, and all were schwannomas with diagnostic criteria suggestive of schwannomatosis. A follow-up of MRI brain and the spine has been planned for the patient, every 3 months in first 6 months, followed again at 6-month interval at 1 year, and then yearly to detect any further recurrence or new lesions.
| Discussion|| |
Neurofibromatosis is a distinct clinical syndrome with two subtypes, namely NF1 and NF2 which has been suggested and recognized by the National Institute of Health (NIH) consensus guidelines for diagnosis., Schwannomatosis, also known as congenital neurilemmotosis, is a rare, distinct clinical syndrome of multiple schwannomas of peripheral nervous system without concomitant involvement of vestibular nerves.,,,, In contrast to schwannomatosis, NF2 is a well-known clinical syndrome distinguished by the presence of bilateral vestibular schwannomas and multiple cranial and spinal tumors., Although schwannomatosis and NF2 are similar, these syndromes are genetically unique and show significant differences in anatomic distribution of lesions, and in clinical presentation, medical management, and patient outcomes.
Various authors have reported about multiple schwannomas without any vestibular symptoms suggesting a distinct syndrome from that of NF2. This favors that schwannomatosis is distinct from other various types described in the literature. At present, there are no NIH diagnostic criteria for the diagnosis of schwannomatosis. Jacoby et al. proposed clinical criteria for the diagnosis of schwannomatosis. They suggested two or more pathologically proven schwannomas and lack of radiological evidence of vestibular tumors at age more than 18 years could be taken as evidence of definite schwannomatosis. If MRI brain is not available, a probable and presumptive diagnosis may be made if patient has two or more pathologically proven schwannomas and no clinical symptoms of eighth cranial nerve at age greater than 30.
Baser et al. proposed some modifications that certainly increase the specificity of diagnostic criteria for schwannomatosis. They proposed that all suspected patients with definite or possible schwannomatosis must not fulfill any of existing criteria of NF2, have no evidence of vestibular schwannoma (VS) on high-resolution MRI, no first-degree relative with NF2, and no constitutional NF2 mutations. The first criterion for the diagnosis of schwannomatosis is the presence of two or more nonintradermal schwannomas in patients older than 30 years, lacks evidence of VS on high-resolution MRI scan, and no constitutional NF2 mutations. The second criteria for the diagnosis of schwannomatosis can be made, if one has the first-degree relative with features suggestive of definite schwannomatosis and has pathologically confirmed one or more nonvestibular system schwannomas, without reference to the age of the patient, MRI findings, and final confirmation by genetic analysis of NF2.
Patients with schwannomatosis represent a small fraction of patients with spinal or peripheral schwannomas who are managed neurosurgically. Seppälä et al. reported an incidence of 3.7% in their series. Huang et al. reported an incidence of 4.6% in their series. Diagnostic criteria for neurofibromatosis (NF2) are presented in [Table 1], and the diagnostic criteria of schwannomatosis are presented in [Table 2]. Chronic pain is another typical feature of schwannomatosis, which was present in our patient. The mean age at diagnosis was 42 years. Our patient presented to us at 40 years almost compatible with age criteria. Our patient had no symptoms of decreased hearing or other lower cranial nerve involvement. Brain MRI showed no intracranial lesion. He was 40 years old and presented with multiple schwannomas, which was histopathologically confirmed. According to the criteria, our patient fulfilled and met criteria laid down for definite schwannomatosis. The surgery was planned, and the patient got operated and improved symptomatically.
Chronic pain is a typical disabling feature of schwannomatosis and impairs the daily routine and activities of the patient. Our patient had chronic pain, disability with pain, difficulty in walking, with fear of getting similar lesions in future, and prompted for surgical management of these lesions, although general rule for asymptomatic lesions is observation and follow-up. In our case, the absence of any features suggestive of NF1/NF2 with chronic pain, age, with histopathologically proven schwannoma characterized schwannomatosis.
Management of symptomatic lesions is surgery as discussed previously. The laminectomy was over-involved site, followed by dural opening, removal of mass, and preservation of roots. Recommended management of asymptomatic lesions is serial MRI spine and brain 3 monthly for 6 months, then 6 monthly for 1 year, and yearly thereafter to detect additional lesions or recurrences.
| Conclusion|| |
Schwannomatosis is a distinct clinical syndrome as compared with neurofibromatosis. The patients with multiple schwannomas should undergo complete screening of the spine and brain and other criteria to rule out NF2. Moreover, schwannomatosis being a benign pathology has better prognosis and outcome as compared to NF2. Asymptomatic lesions can be managed conservatively with serial imaging most frequently at yearly intervals as discussed above. Schwannomas have good prognosis and should be operated as indicated. The patients are advised for regular follow-up and imaging and for the development of any neurological or clinical features suggestive of recurrence or development of newer lesions, as these patients have propensity to develop fresh lesions at any time.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2]