Posterior fossa melanocytic schwannoma extending to the cervicothoracic spinal cord: A clinical rarity
- Department of Neurosurgery, The Aga Khan University Hospital, Karachi, Pakistan.
Ahsan Ali Khan, Senior Instructor, Department of Neurosurgery, The Aga Khan University Hospital, Pakistan.
DOI:10.25259/SNI_183_2022Copyright: © 2022 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Zoha Zahid Fazal, Syeda Maryam Kazmi, Mohammad Hamza Bajwa, Ahsan Ali Khan. Posterior fossa melanocytic schwannoma extending to the cervicothoracic spinal cord: A clinical rarity. 26-Aug-2022;13:375
How to cite this URL: Zoha Zahid Fazal, Syeda Maryam Kazmi, Mohammad Hamza Bajwa, Ahsan Ali Khan. Posterior fossa melanocytic schwannoma extending to the cervicothoracic spinal cord: A clinical rarity. 26-Aug-2022;13:375. Available from: https://surgicalneurologyint.com/surgicalint-articles/11836/
Background: Melanocytic schwannomas (MSs) are rare, malignant peripheral nerve sheath tumors with only 200 cases reported to date. These pose imaging and pathological challenges for definitive diagnosis.
Case Description: A 25-year-old lady presented at our center with a prolonged history of gait disturbance, left ear tinnitus, headaches, and drowsiness. MRI findings showed a midline cystic lesion in the posterior cranial fossa extending caudally to the D1 vertebral body, with marked central hypointensity, and peripheral hyperintensity on T1-weighted images. A suboccipital craniotomy and debulking of the lesion were performed, showing a hyperpigmented, infiltrative tumor adherent to the surrounding structures. This was confirmed as a melanocytic schwannoma on histopathological analysis.
Conclusion: Posterior fossa MSs involving cervicomedullary region and extending distally to cervicothoracic spinal cord are rare and complex cases, particularly with regard to difficulty diagnosing preoperatively and surgical resection.
Keywords: Cervicothoracic, Melanocytic schwannoma, Neuro-oncology, Posterior fossa
Melanocytic schwannomas (MSs) are a rare variant of benign Schwann cell neoplasms typically arising in the early middle age with a predilection for extracranial regions.[
A 25-year-old right-handed lady presented to our neurosurgery clinic with progressively worsening complaints of gait disturbance, left ear tinnitus, headaches, and drowsiness for the past 6 months. On neurological examination, she exhibited hyperreflexia in both arms and left lower leg and was unable to walk in a straight line.
Preoperative MRI scans showed a solid-cum-cystic lesion with enhancement along the midline in the posterior fossa extending distally into the cervical spinal cord reaching to the level of upper endplate of the D1 vertebral body, measuring approximately 13.3 × 4.6 × 3.4 cm [
Preoperative MRI images: (a) Coronal T1-weighted image showing a posterior fossa lesion with a homogeneous center and peripheral high-signal intensity rim, seen to be extending down through to the cervicomedullary junction. Upward displacement of the brainstem can be seen as well as the basilar artery, with compression of the cerebellum. (b) Coronal T2-weighted image. Postoperative MRI images: (c) Coronal T1-weighted image with posterior resection cavity. (d) Coronal T2-weighted image. (e and f) Coronal T1-weighted and T2-weighted images showing extension of the lesion to the thoracic spinal cord. (g and h) Axial T2-weighted images depicting the lesion at the skull base and craniocervical junction, pre- and postoperatively.
We performed a suboccipital craniotomy for resection of the lesion. For improved exposure, part of the C1 ring was removed and cisterna magna opened. A hyper-pigmented and black colored tumor with no clear margins was visualized [
Postoperatively, the patient had an uneventful hospital course and discharged home on the 3rd day after surgery. On the most recent follow-up, her drowsiness and headaches had improved, with some difficulty in walking requiring support. She was referred to medical and radiation oncology services for further management.
MS may present in the craniovertebral junction (CVJ) with no pathognomonic signs as 29% of cases present asymptomatically.[
Spinal instability and progressive neuropathy are strong indications for operative intervention in craniocervical MS.[
Recent literature advocates for MS to be considered a malignant entity with incompletely excised tumors involving the neurovasculature having the worst prognosis. In the largest series, Torres-Mora et al. found rates of 42% distant metastases, 35% local recurrence, and 27% disease-specific mortality.[
Posterior fossa MS involving CVJ and spinal cord distally poses a significant neurosurgical challenge in terms of diagnosis and successful intervention. Careful preoperative evaluation and intraoperative prudence are crucial for optimal management.
Declaration of patient consent
Patient’s consent not required as patient’s identity is not disclosed or compromised.
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Conflicts of interest
There are no conflicts of interest.
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