CASE REPORT |
https://doi.org/10.5005/jojs-10079-1128 |
Ancient Schwannoma Presenting as Sciatica Mimicker: A Case Report
1–3Department of Spine Surgery, Medical Trust Hospital, Kochi, Kerala, India
4Department of Pathology, Medical Trust Hospital, Kochi, Kerala, India
Corresponding Author: Krishnakumar Ramachandran, Department of Spine Surgery, Medical Trust Hospital, Kochi, Kerala, India, Phone: +91 9207570169, e-mail: krishnakumar.ram@gmail.com
Received: 17 October 2023; Accepted: 08 November 2023; Published on: 12 January 2024
ABSTRACT
Sciatica is the pain that radiates from the lower back or buttock to the posterior thigh, calf, and towards the foot. The most common cause of sciatica is intervertebral disc prolapse or degenerative spinal conditions. A few rare conditions also cause sciatica-like symptoms, termed sciatica mimicker. A case report of a 26-year-old male with back pain and radiating pain to both lower limbs. On examination, he had a positive straight leg raising test (SLR). On Magnetic resonance imaging, he had an intradural extramedullary tumor (IDEM) at the L1 level. He underwent posterior decompression and surgical resection of the tumor. Histopathological examination (HPE) consistent with Schwannoma. Lumbar schwannoma is a benign slow-growing intradural extramedullary tumor presented as a sciatica mimicker. After surgery, the patient becomes symptomatically better.
How to cite this article: S VA, Ramachandran K, HD B, et al. Ancient Schwannoma Presenting as Sciatica Mimicker: A Case Report. J Orth Joint Surg 2024;6(1):84–86.
Source of support: Nil
Conflict of interest: None
Keywords: Ancient schwannoma, Case report, IDEM, Sciatica mimicker
CASE DESCRIPTION
A 26-year-old male electric engineer by occupation came to our outpatient clinic with lower back pain radiating to both lower limbs for a period of 1 year. Initially, the patient had back pain, which gradually progressed to radicular pain, which was severe in the last 3 months. The patient’s activity of daily living is severely affected. He left the job because of the pain. He also has the symptoms of neurogenic claudication. He cannot stand for >20 minutes. His bowel and bladder were preserved. On spine examination, his straight leg raising test was 45° on both sides, and his knee flexion was 4/5 (on the Medical Research Council scale) on the right side. Sensory dulling was noted on both lower limbs. His plantar reflex was mute. The patient underwent further investigations in the form of radiographs and magnetic resonance imaging (MRI). The X-rays were normal. MRI shows a well-circumscribed hyperintense lesion over the lumbar (L3) on T2 and hypointense on T1, suggesting an intradural and extramedullary lesion of the lumbar region. The differential diagnosis was made at this stage as nerve sheath tumor, schwannoma, considering the age of the patient (Fig. 1A). The treatment options have been discussed with the patient, which is more of surgical interventions. (Fig. 1B). The patient had laminectomy of L3 and removal of the tumor using microscopic magnification under intraoperative somatosensory and motor-evoked potential monitoring throughout the procedure (Fig. 2). His postoperative period was uneventful. His symptoms came down significantly. The tumor was sent for histopathological examination. It shows circumscribed and encapsulated biphasic neoplasms composed of compact hypercellular and myxoid hypocellular areas. Nuclear palisading around the fibrillary process produces the verocay bodies seen. These features are suggestive of benign nerve sheath tumors consistent with ancient schwannoma (Fig. 3). Further immunohistochemical markers were carried out; it was diffusely immunoreactive for S100, SOX 10, and Ki 67 proliferation index was 5% again consistent for schwannoma. The patients were followed up at 3 and 6 weeks, 3 and 6 months, and 1 year following the surgery. He was assessed clinically and radiologically. His motor power was increased, and his activity of daily living was increased. At 3 months, a follow-up MRI was taken, and it showed complete resolution of the tumor (Fig. 4).
Figs 1A and B: (A) Sagittal and axial section shows hypointense in T1, hyperintense in T2, and well-defined intradural extramedullary lesion noted at L3 vertebral level; (B) The lesion is completely filling the thecal sac with severe compression and peripheral displacement of cauda equina nerve roots; suggestive of benign nerve sheath tumor
Fig. 2: Tumor specimen after the removal
Fig. 3: HPE shows biphasic neoplasm, foci showing more nuclear atypia (degenerative), nuclear palisading producing verocay bodies suggestive of ancient schwannoma
Fig. 4: Shows T2 sagittal showing complete resolution of the tumor with postoperative changes at the L3 level
DISCUSSION
On reviewing the literature, there were various causes described under sciatica mimicker. A study by Mukesh et al. on sciatica mimicker, aneurysmal bone cyst, proximal femur osteomyelitis, epidural abscess, hemangiopericytoma, neurofibroma, facetal cyst, metastatic tumor, arachnoid cyst, giant cell tumor of L3 vertebra, Liposarcoma around L4 nerve sheath were listed to be as sciatica mimicker.1 They also conclude in their study that all sciatica was not due to a discogenic cause, to consider other pathologies when a straight leg test is positive with leg pain. Schwannoma is the most common benign nerve sheath neoplasm affecting the peripheral nerve system. Schwannoma can occur at any age but is more common between 30 and 40 years.2 Various forms of schwannoma are noted, such as cellular schwannoma, plexiform schwannoma, and ancient schwannoma.2 Ancient schwannoma is the one when the tumor has nuclear pleomorphism and occasional mitotic figures. Verocay bodies are pathognomonic of schwannoma, which is the nuclear palisading pattern on histopathological examination (HPE). Immunohistochemical (IHC) markers, such as S100, SOX 10, calretinin, and Leu-7, were diffusely immunoreactive for schwannoma.2 The malignant transformation is rare.2 The schwannoma affecting the intradural has more male predominance. The intradural schwannoma manifests as well as a demarcated spinal cord mass with intense enhancement. MRI of schwannoma reveals a well-circumscribed T1 iso-/hypointense and T2 hyperintense nodular intradural mass with associated enhancement, most often arising from the lumbar dorsal sensory nerve root. Surgical resection was the followed treatment when the tumor was symptomatic or increasing in size on follow-up imaging.3 This case study explains the schwannoma over the lumbar region presented as sciatica in young males. The clinical features are more consistent for sciatica; when an MRI is done, it favors benign nerve sheath tumors. The patient had undergone complete resection of the tumor with somatosensory evoked potential and motor evoked potential. Further, HPE and IHC were also consistent for ancient schwannoma. This benign tumor has a good prognosis and good relief of pain after the surgical resection.4
There are case reports in the literature that have noted the schwannoma in the thoracic and lumbar region has produced sciatica-like symptoms.5,6 When surgically treated, those patients were improved better. They also have concluded in their studies that tumors in the cauda equina region should be considered as the differentials when this patient has sciatica-like symptoms and has not improved on the conservative treatment, and these patients should be ordered for MRI to confirm the diagnosis.7
CONCLUSION
Sciatica mimickers are the condition when the straight raise leg test is positive and not due to a discogenic cause. In our case report, the patient had schwannoma as a sciatica mimicker; after the complete surgical resection, the patient’s symptoms were significantly improved. This benign tumor has a good prognosis after the surgical resection.8
ORCID
Vijaya Anand S https://orcid.org/0000-0002-3397-8377
REFERENCES
1. Kumar K, R K. Sciatica mimickers. Int J Cur Res 2016;8(12):43895–43900.
2. Antonescu CR, Louis DN, Hunter S, et al. Schwannoma. WHO Classification of Tumours of the Central Nervous System, 4th edition. Lyon, France: IARC; 2016. pp. 214–218.
3. Koeller KK, Shih RY. Intradural extramedullary spinal neoplasms: radiologic-pathologic correlation. Radiographics 2019;39(2):468–490. DOI: 10.1148/rg.2019180200
4. Gonzalvo A, Fowler A, Cook RJ, et al. Schwannomatosis, sporadic schwannomatosis, and familial schwannomatosis: a surgical series with long-term follow-up. Clinical article. J Neurosurg 2011;114(3):756–762. DOI: 10.3171/2010.8.JNS091900
5. Chu EC, Trager RJ, Yee WJ, et al. Lumbar schwannoma as a rare cause of radiculopathy in the chiropractic office: a case report. Cureus 2022;14(11):e31758. DOI: 10.7759/cureus.31758
6. Chu EC, Trager RJ. Thoracic schwannoma as an unusual cause of sciatic pain in the chiropractic office: a case report. Am J Case Rep 2022;23:e938448. DOI: 10.12659/AJCR.938448
7. Abul-Kasim K, Thurnher MM, McKeever P, et al. Intradural spinal tumors: current classification and MRI features. Neuroradiology 2008;50(4):301–314. DOI: 10.1007/s00234-007-0345-7
8. Rustagi T, Badve S, Parekh AN. Sciatica from a foraminal lumbar root schwannoma: case report and review of literature. Case Rep Orthop 2012;2012:142143. DOI: 10.1155/2012/142143
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