|Year : 2020 | Volume
| Issue : 1 | Page : 45-47
Giant lumbar extraforaminal schwannoma
Rohit Balasubramanian1, Subhash Kale2, Vignesh Kanda Kumar3, Sagar Ghodasara1, Udaykumar Badhe1
1 Department of Neurosurgery, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
2 Department of Plastic Surgery, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
3 Department of Medical oncology, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
|Date of Submission||19-May-2020|
|Date of Acceptance||04-Jun-2020|
|Date of Web Publication||2-Jul-2020|
Dr. Rohit Balasubramanian
OPD No. 13, Kovai Medical Centre and Hospital, 99 Avinashi Road, Civil Aerodrome Post, Coimbatore - 641 014, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Schwannomas are dumb-bell shaped benign intradural or extradural spinal canal nerve sheath tumors. Here, we present the rare case of a lumbar canal schwannoma in a middle-aged man. The tumor was completely extraforaminal with scalloping of the bone. Gross total excision was achieved by a lumbar approach.
Keywords: Extraforaminal schwannomas, giant-spinal schwannomas, lumbar neurogenic tumor, nerve sheath tumor
|How to cite this article:|
Balasubramanian R, Kale S, Kumar VK, Ghodasara S, Badhe U. Giant lumbar extraforaminal schwannoma. Int J Neurooncol 2020;3:45-7
| Introduction|| |
Schwannomas are the most common nerve sheath tumors. Spinal schwannomas account for about 25% of intradural spinal cord tumors in adults. Most of them are solitary lesions that can occur throughout the spinal canal; however, the extraforaminal type is uncommon. It has no gender bias, and the lumbar and cervical regions are most commonly affected as they arise from the Schwann cell progenitor cells. They are benign, well delineated, and encapsulated tumors. When multiple schwannomas are present in one individual, it is referred to as “Schwannomatosis.” Schwannomatosis is the third-most common form of neurofibromatosis and is present in 3%–4% of schwannoma patients. It is a disease that is both genetically and clinically distinct from nonsyndromic schwannomas, and therefore, should be treated suitably.
Giant Spinal Schwannomas (GSS) are rarely described in the literature and particularly affect the retroperitoneal space with an incidence between 0.7% and 2.7%. It is considered “Giant” if it spans two or more vertebral levels. As they are usually asymptomatic, and early diagnosis is challenging. However, nonspecific abdominal or vague back pain may occur. The prime goal of the surgery is the gross total resection of the lesion to avoid recurrence. However, giant retroperitoneal schwannomas present with several challenges, especially in terms of the best surgical approach, due to its close relationship with vital abdominal and retroperitoneal structures. Here, we discuss a rare case of lumbar extraforaminal schwannoma which was approached by a lateral lumbar approach.
| Case Report|| |
A 58-year-old male presented with ambiguous low backache radiating to the right leg, progressive in nature, for 2 years. He was treated medically with analgesics and physiotherapy by a local doctor. As the pain was refractory, he was advised a magnetic resonance imaging (MRI) lumbar spine, which revealed a heterogeneously enhancing extraforaminal high-signal lesion in the right paravertebral region along the course of the exiting nerve root at L2–L3 level, (5.5 cm × 3.6 cm × 3 cm [CC × TR × AP]) extending into the psoas muscle [Figure 1]. Computed tomography (CT) lumbar spine revealed scalloping of the vertebra without foraminal widening or intratumoral calcifications. The lesion was seen displacing the right psoas muscle anteriorly and laterally [Figure 1].
|Figure 1: Preoperative images… (a) Magnetic resonance imaging lumbar spine axial T2 showing mixed intensity lesion in the right paraspinal region displacing psoas muscle laterally. (b) Magnetic resonance imaging lumbar region coronal cut showing lesion in the right para vertebral region at L2–L3 level displacing psoas muscle laterally. (c) Computed tomography lumbar region coronal cut showing hypodense lesion in the right lumbar region starting at the lower pole of the right kidney. (d) Computed tomography region sagittal cut showing psoas muscle displacing laterally and anteriorly. (e) USG lumbar region with color Doppler showing mixed echogenic lesion with reduced vascularity|
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USG-guided Trucut biopsy of the lesion was done at the department of oncology at our institution. It showed a linear core of the tissue with hypocellular neoplasm with predominance of loose collagenous stroma interspaced with few scattered spindle cells with elongated hyperchromatic nuclei with depressed chromatin and conspicuous nucleoli, suggestive of a spindle-cell lesion possibly of neural or smooth muscle origin. A neurosurgery referral was sought and surgery was planned in liaison with the plastic surgeon.
A right lumbar exploration was done using a right lateral lumbar incision. Dissection was done through the muscular planes with muscle splitting. The tumor was identified after the recognition and splitting of the right psoas muscle along its fibers [Figure 2]. Tumor was encapsulated, grayish white in color with a rubbery consistency, and with mild-to-moderate vascularity. The nerve was identified at the caudal end and traced cranially, which was thinned out on the anteromedial aspect of tumor. The lesion was released from all sides, and extracapsular excision of tumor was done, along with a thin sleeve of the nerve root on both sides.
|Figure 2: Intraoperative images… (a) Planned incision on the right lateral lumbar region oriented medial to lateral. (b) Exposure by muscle splitting till retroperitoneal fat. (c) Tumor located after splitting psoas muscle. (d) Excised specimen|
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Postoperatively, the patient developed numbness over the anterior aspect of the right thigh without any gross motor deficit. Postoperative contrast CT showed no residual lesion. He was mobilized and discharged on postoperative day 3.
Histopathology revealed predominantly hypercellular areas, edematous stroma, hyalinization, and a few thick-walled blood vessels with hemorrhage. Foci of hypercellularity with spindle cells having plumb nuclei were seen. Nerve bundles and adipose tissue were seen surrounding the lesion. These features were suggestive of an schwannoma.
| Discussion|| |
Nerve sheath tumors originate from the Obersteiner-Redlich area-the junction of the transition of oligodendrocytes to Schwann cells. Schwannomas usually develop from the dorsal nerve roots and are generally located intradurally and extramedullary. They can extend into the foraminal and extraforaminal areas, leading to an extradural lesion. Schwannomas are encapsulated and originate from single nerve fascicles that display progressive growth characteristics. They may occur sporadically or in association with NF-2, Schwannomatosis or Carny complexes.
“Giant Schwannomas” are rare and account for 0.3%–5% of tumors affecting the retroperitoneal space. It typically presents as a well-encapsulated lesion, free from adherence to the surrounding tissues. Due to its insidious behavior and slow-growing nature, they are usually diagnosed late. However, larger lesions present more aggressively, with local compression, adherence, and bone rearrangement.
Clinical presentations of “Giant Spinal Schwannomas” (GSS) may vary based on the several factors such as the location, extension of the tumor, and the duration of compression. In larger tumors, neural structures and adjacent organs may get compressed. In extraforaminal thoracic GSSs, compression of the lungs and vascular structures may occur. In the lumbosacral region, it can compress abdominal and visceral structures, resulting in urinary problems and constipation. The most frequent presenting complaint is usually low backache and radicular pain, also seen in our patient.
MRI is the ideal method for the diagnosis and for eliminating differentials. On MRI, GSSs are isointense on T1 and hyperintense on T2-weighted magnetic resonance sequences. Cystic and necrotic zones maybe witnessed in GSSs which may not be present in classic schwannomas. In such cases, preoperative diagnosis must be supported with percutaneous biopsies.
In our patient, preoperative diagnostic biopsy was performed. Cystic components, calcific foci, and bony destruction can also be observed in some cases. CT is useful in identifying bony erosion, foraminal widening, and foci of calcifications which helps in excluding other differential diagnoses.,
Surgery remains the treatment of choice for GSS. Surgical approach varies according to the location and extension of tumor. Transparaspinal and lumbar exposure, both provide direct and safe routes for resection of these tumors, especially in the extraforaminal region. Transparaspinal approach is based on the two concepts. First, though the lumbar or paraspinal muscles are sectioned, there are minimal biomechanical penalties. Second, there is a surgical plane between the adjacent neural and vascular structures and the tumor capsule. Lumbar exposure is usually done through a lateral lumbar incision and splitting of muscles planes, which avoids muscle cutting and thus avoids damage to muscle and also preserves muscle strength circumventing biomechanical compromise. In our case, the lesion was spread over two vertebral bodies scalloping the lateral side of the vertebral body; hence, lumbar approach was chosen over transparaspinal approach. This allowed the complete removal of tumor from a single lateral lumbar approach, without bony violation and biomechanical compromise.,,,
| Conclusion|| |
Extraforaminal schwannoma in the lumbar region is a rare condition. In our case, not only was the lesion rare, but a lumbar approach for extraforaminal lumbar lesion was highlighted, which provided a wider operative field of vision compared to the paraspinal approach.
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]