- Email: [email protected]
Epidermoid Cyst of the Lumbar Spine after Lumbar Puncture: A Clinical, Radiographic, and Pathological Correlation
Journal Pre-proof Epidermoid Cyst of the Lumbar Spine after Lumbar Puncture: A Clinical, Radiographic, and Pathological Correlation Vincent Dodson, BS, Neil Majmundar, MD, Leroy R. Sharer, M.D., John L. Gillick, MD PII:
S1878-8750(20)30270-9
DOI:
https://doi.org/10.1016/j.wneu.2020.02.008
Reference:
WNEU 14282
To appear in:
World Neurosurgery
Received Date: 17 November 2019 Accepted Date: 1 February 2020
Please cite this article as: Dodson V, Majmundar N, Sharer LR, Gillick JL, Epidermoid Cyst of the Lumbar Spine after Lumbar Puncture: A Clinical, Radiographic, and Pathological Correlation, World Neurosurgery (2020), doi: https://doi.org/10.1016/j.wneu.2020.02.008. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier Inc.
Epidermoid Cyst of the Lumbar Spine after Lumbar Puncture: A Clinical, Radiographic, and Pathological Correlation Vincent Dodson, BS, Neil Majmundar, MD, Leroy R. Sharer, M.D., John L. Gillick, MD
Department of Neurological Surgery, and Department of Pathology, Immunology and Laboratory Medicine, Rutgers New Jersey Medical School, Newark, New Jersey
Address for Correspondence and Reprints: John L. Gillick, MD Department of Neurological Surgery Rutgers New Jersey Medical School 90 Bergen St, Suite 8100 Newark, New Jersey Email: [email protected]
Key Words: epidermoid cyst, lumbar spine, iatrogenic, keratinization Running Head: Epidermoid Cyst of the Lumbar Spine Conflicts of Interest: None Disclosure of Funding: None Word Count: 916
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Abstract Background and Importance: Epidermoid cysts can rarely arise as a late complication of lumbar puncture. We describe a young man who had a remote history of a lumbar puncture, and who was subsequently found to have a lumbar spinal epidermoid cyst on imaging, after presenting with lower extremity radicular pain. Clinical Presentation: A 24-year-old male with a remote history of lumbar puncture presented with lower back pain and radicular leg pain which had been ongoing for over a year. Despite conservative management, the patient’s symptoms progressed to worsening back pain and left L4 radiculopathy. Magnetic Resonance Imaging (MRI) of the lumbar spine demonstrated a peripherally enhancing, intradural, extramedullary lesion at L4/5. Diffusion-weighted imaging (DWI) revealed diffusion restriction within the lesion, characteristic of an epidermoid cyst. The patient underwent an L4-L5 laminectomy for resection of the intradural tumor. The lesion was noted to contain pearly white granules consistent with the appearance of an epidermoid cyst. Histopathology confirmed the diagnosis. On follow up examination, the patient demonstrated improvement of his back pain and resolution of radicular symptoms. Conclusion: Lumbar spinal epidermoid cysts may be either congenital or secondary to an iatrogenic cause. This patient had a remote history of lumbar puncture during work-up for meningitis as a child. As a complication of a lumbar puncture, the formation of an epidermoid cyst can occur and is thought to be the result of implanted cutaneous tissue. This case provides a comprehensive illustration of the clinical, radiographic, intraoperative, and pathological findings consistent with an iatrogenic epidermoid cyst.
1
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Introduction Iatrogenic epidermoid cysts can arise as a late complication of lumbar puncture. These rare tumors are slow-growing and typically present years after the initiating event. As symptoms are nonspecific, diagnosis is aided by a comprehensive history, imaging, and histopathology. In most cases, definitive treatment consists of a laminectomy followed by gross total resection of the lesion. We present a case of a young male adult with a remote history of lumbar puncture who developed an epidermoid cyst many years after the lumbar puncture. Clinical Presentation A 24-year-old male initially presented with consistent lower back pain for several months. The patient also reported numbness and pain which radiated down his left lower extremity. He did not have any motor weakness on neurological examination. His past medical history was significant for a remote history of a lumbar puncture as a child as part of a meningitis work-up. Despite treatment with conservative measures, the patient’s symptoms progressed to worsening back pain and left L4 radiculopathy. MRI of the lumbar spine demonstrated a cystic lesion at L4/5 with some peripheral enhancement. Further diffusion-weighted imaging revealed restriction within the lesion (Figure 1). Given the progression of symptoms, failure of conservative management, and the convincing imaging findings, surgery was performed. The patient consented to surgical intervention and to the use of his imaging and pathological studies for educational purposes. An L4-L5 laminectomy was performed, followed by gross total resection of the intradural lesion. The lesion was noted to contain cholesterol-like granules consistent with the appearance of an epidermoid cyst, which was suspected based on the imaging findings. The cystic material was subsequently resected, and the remnants that were adherent to the descending L4 and L5 nerve roots were cauterized with bipolar cautery forceps. The histological diagnosis confirmed epidermoid cyst (Figures 2a and 2b). The patient tolerated the surgery well; all motor potentials, electromyographic (EMG) activity, and sensory activity were stable, at baseline levels. On follow up examination, the patient demonstrated significant improvement of his back pain and resolution of his radicular symptoms. Discussion Epidermoid cysts are characterized in histological studies by squamous epithelium and keratinocytes with amorphous material suggesting keratinization. They may occur congenitally or iatrogenically. In congenital cases, they are usually associated with spinal dysraphisms such as spina bifida, while iatrogenic cases are most often attributed to a history of lumbar puncture, often repeated.1 In a study from 1962, Manno et al. found that 41% of 90 patients developed iatrogenic epidermoid cysts which could be attributed to the implantation of epidermis.2 Some have speculated that the reduced incidence of iatrogenic epidermoid cysts in modern times is due to the widespread use of styletted needles. Even with styletted needles, iatrogenic epidermoid cysts have been reported to occur, especially in cases in which the stylet is ill-fitting or when the lumbar puncture is repeated.3,4 Epidermoid cysts are slow-growing lesions, such that the onset of symptoms after the initial lumbar puncture may take several years.2 Symptoms develop as the cyst grows and causes compression of the adjacent neurologic structures. Initial symptoms are usually non-specific.
2
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Patients may experience a dull and localized back pain, numbness or weakness of the lower extremities, and incontinence.5 Symptoms depend upon the location as well as the nerve roots which are compressed. On MRI, epidermoid cysts are typically isointense to the surrounding cerebrospinal fluid. The lesion is usually well defined and peripherally enhances with gadolinium administration, as seen in this case.6 DWI can help to distinguish epidermoid cysts from arachnoid cysts, with the former demonstrating diffusion restriction while the latter does not.7 However, a definitive diagnosis is made histologically, demonstrating a cyst wall composed of keratinizing stratified squamous epithelium.5 In symptomatic cases, laminectomy with surgical resection is the treatment of choice. In most cases, a gross total resection can be accomplished safely.8 Often, the epidermoid cyst is adherent to surrounding neural tissue, which would require less aggressive subtotal resection and the use of EMG and somatosensory evoked potentials (SSEPs) to ensure postoperative intact neurologic function. The SSEP of the lower extremity can detect the integrity of the cauda equina through L4 to S1, and the EMG is used to detect the external anal sphincter activity to ensure the integrity of the S2-S4 nerve roots.9 Gross total resection is facilitated by proper microsurgical technique and the use of an ultrasonic surgical aspirator for debulking.7,9 While uncommon, recurrence may occur in cases of subtotal resection. While gross total resection is possible in a majority of cases, the tendency of these tumors to be adherent to surrounding tissue can in some cases leave tumor tissue behind, increasing the likelihood of recurrence. There is at least one documented case of a recurrent epidermoid cyst which required repeat surgery and the placement of an Ommaya reservoir for continual drainage.7 Tumor regrowth typically takes years, and atypical hyperplasia is exceedingly rare, though it has been documented.10 Conclusion While spinal epidermoid cysts are rare, they may arise as congenital lesions or as complications after lumbar puncture. In this case, the patient had a remote history of lumbar puncture during work-up for meningitis as a child. As a complication of lumbar puncture, the formation of an epidermoid cyst can occur and is thought to be the result of implanted cutaneous tissue. Therefore, it is necessary, as in all cases working up a non-specific symptom, to obtain a comprehensive history from both the patient and the family. This case provides an illustration of the clinical, radiographic, intraoperative, and pathological findings consistent with an iatrogenic epidermoid cyst. References 1. McDonald JV, Klump TE. Intraspinal epidermoid tumors caused by lumbar puncture. Archives of neurology. 1986;43(9):936-939. 2. Manno NJ, Uihlein A, Kernohan JW. Intraspinal epidermoids. Journal of neurosurgery. 1962;19:754-765. 3. Issaivanan M, Cohen S, Mittler M, Johnson A, Edelman M, Redner A. Iatrogenic spinal epidermoid cyst after lumbar puncture using needles with stylet. Pediatric hematology and oncology. 2011;28(7):600-603.
3
117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
4. 5.
6.
7. 8. 9.
10.
Per H, Kumandas S, Gumus H, Yikilmaz A, Kurtsoy A. Iatrogenic epidermoid tumor: late complication of lumbar puncture. Journal of child neurology. 2007;22(3):332-336. Yin H, Zhang D, Wu Z, Zhou W, Xiao J. Surgery and outcomes of six patients with intradural epidermoid cysts in the lumbar spine. World journal of surgical oncology. 2014;12:50-50. Amato VG, Assietti R, Arienta C. Intramedullary epidermoid cyst: preoperative diagnosis and surgical management after MRI introduction. Case report and updating of the literature. Journal of neurosurgical sciences. 2002;46(3-4):122-126. Fleming C, Kaliaperumal C, O'Sullivan M. Recurrent intramedullary epidermoid cyst of conus medullaris. BMJ case reports. 2011;2011:bcr1120115090. Beechar VB, Zinn PO, Heck KA, et al. Spinal Epidermoid Tumors: Case Report and Review of the Literature. Neurospine. 2018;15(2):117-122. Liu H, Zhang JN, Zhu T. Microsurgical treatment of spinal epidermoid and dermoid cysts in the lumbosacral region. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. 2012;19(5):712-717. Li J, Qian M, Huang X, Zhao L, Yang X, Xiao J. Repeated recurrent epidermoid cyst with atypical hyperplasia: A case report and literature review. Medicine. 2017;96(49):e8950-e8950.
Figures Figure 1: Preoperative and postoperative imaging. A) Preoperative T1 weighted sagittal MRI with gadolinium of the lumbar spine demonstrating a peripherally enhancing lesion within the spinal canal. B) Preoperative T2 weighted sagittal MRI of the lumbar spine demonstrating cystic lesion located ventral to the thecal sac. C) Preoperative diffusion-weighted sagittal MRI demonstrating a diffusion restriction within the lesion. D) Immediate postoperative T1 weighted sagittal MRI with gadolinium demonstrating successful removal of cyst. E) Immediate postoperative T2 weighted sagittal MRI of the lumbar spine demonstrating successful removal of cyst. F) Preoperative T2 weighted axial MRI of the L4-L5 disc space demonstrating compression of the thecal sac. The cyst occupies most of the spinal canal. G) 6-month postoperative T1 weighted axial MRI with gadolinium of the L4-L5 disc space demonstrating successful removal of cyst. H) 6-month postoperative T2 weighted axial MRI of the L4-L5 disc space demonstrating successful removal of cyst. Figure 2: A) Keratinizing squamous epithelium of epidermoid cyst, with exfoliated keratin material into the cyst cavity. Hematoxylin and eosin stain, original magnification 100X. B) Rhomboid cholesterol crystals from interior of epidermoid cyst, touch preparation of unfixed specimen. Hematoxylin and eosin stain, original magnification 100X.
4
MRI-Magnetic Resonance Imaging DWI-Diffusion-weighted imaging EMG-electromyography SSEPs-somatosensory evoked potentials
The authors, Vicent Dodson, Neil Majmundar, Leroy Sharer, and John L. Gillick have no conflicts of interest to report in regards to the submission of this manuscript for World Neurosurgery.
S1878-8750(20)30270-9
DOI:
https://doi.org/10.1016/j.wneu.2020.02.008
Reference:
WNEU 14282
To appear in:
World Neurosurgery
Received Date: 17 November 2019 Accepted Date: 1 February 2020
Please cite this article as: Dodson V, Majmundar N, Sharer LR, Gillick JL, Epidermoid Cyst of the Lumbar Spine after Lumbar Puncture: A Clinical, Radiographic, and Pathological Correlation, World Neurosurgery (2020), doi: https://doi.org/10.1016/j.wneu.2020.02.008. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier Inc.
Epidermoid Cyst of the Lumbar Spine after Lumbar Puncture: A Clinical, Radiographic, and Pathological Correlation Vincent Dodson, BS, Neil Majmundar, MD, Leroy R. Sharer, M.D., John L. Gillick, MD
Department of Neurological Surgery, and Department of Pathology, Immunology and Laboratory Medicine, Rutgers New Jersey Medical School, Newark, New Jersey
Address for Correspondence and Reprints: John L. Gillick, MD Department of Neurological Surgery Rutgers New Jersey Medical School 90 Bergen St, Suite 8100 Newark, New Jersey Email: [email protected]
Key Words: epidermoid cyst, lumbar spine, iatrogenic, keratinization Running Head: Epidermoid Cyst of the Lumbar Spine Conflicts of Interest: None Disclosure of Funding: None Word Count: 916
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Abstract Background and Importance: Epidermoid cysts can rarely arise as a late complication of lumbar puncture. We describe a young man who had a remote history of a lumbar puncture, and who was subsequently found to have a lumbar spinal epidermoid cyst on imaging, after presenting with lower extremity radicular pain. Clinical Presentation: A 24-year-old male with a remote history of lumbar puncture presented with lower back pain and radicular leg pain which had been ongoing for over a year. Despite conservative management, the patient’s symptoms progressed to worsening back pain and left L4 radiculopathy. Magnetic Resonance Imaging (MRI) of the lumbar spine demonstrated a peripherally enhancing, intradural, extramedullary lesion at L4/5. Diffusion-weighted imaging (DWI) revealed diffusion restriction within the lesion, characteristic of an epidermoid cyst. The patient underwent an L4-L5 laminectomy for resection of the intradural tumor. The lesion was noted to contain pearly white granules consistent with the appearance of an epidermoid cyst. Histopathology confirmed the diagnosis. On follow up examination, the patient demonstrated improvement of his back pain and resolution of radicular symptoms. Conclusion: Lumbar spinal epidermoid cysts may be either congenital or secondary to an iatrogenic cause. This patient had a remote history of lumbar puncture during work-up for meningitis as a child. As a complication of a lumbar puncture, the formation of an epidermoid cyst can occur and is thought to be the result of implanted cutaneous tissue. This case provides a comprehensive illustration of the clinical, radiographic, intraoperative, and pathological findings consistent with an iatrogenic epidermoid cyst.
1
25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
Introduction Iatrogenic epidermoid cysts can arise as a late complication of lumbar puncture. These rare tumors are slow-growing and typically present years after the initiating event. As symptoms are nonspecific, diagnosis is aided by a comprehensive history, imaging, and histopathology. In most cases, definitive treatment consists of a laminectomy followed by gross total resection of the lesion. We present a case of a young male adult with a remote history of lumbar puncture who developed an epidermoid cyst many years after the lumbar puncture. Clinical Presentation A 24-year-old male initially presented with consistent lower back pain for several months. The patient also reported numbness and pain which radiated down his left lower extremity. He did not have any motor weakness on neurological examination. His past medical history was significant for a remote history of a lumbar puncture as a child as part of a meningitis work-up. Despite treatment with conservative measures, the patient’s symptoms progressed to worsening back pain and left L4 radiculopathy. MRI of the lumbar spine demonstrated a cystic lesion at L4/5 with some peripheral enhancement. Further diffusion-weighted imaging revealed restriction within the lesion (Figure 1). Given the progression of symptoms, failure of conservative management, and the convincing imaging findings, surgery was performed. The patient consented to surgical intervention and to the use of his imaging and pathological studies for educational purposes. An L4-L5 laminectomy was performed, followed by gross total resection of the intradural lesion. The lesion was noted to contain cholesterol-like granules consistent with the appearance of an epidermoid cyst, which was suspected based on the imaging findings. The cystic material was subsequently resected, and the remnants that were adherent to the descending L4 and L5 nerve roots were cauterized with bipolar cautery forceps. The histological diagnosis confirmed epidermoid cyst (Figures 2a and 2b). The patient tolerated the surgery well; all motor potentials, electromyographic (EMG) activity, and sensory activity were stable, at baseline levels. On follow up examination, the patient demonstrated significant improvement of his back pain and resolution of his radicular symptoms. Discussion Epidermoid cysts are characterized in histological studies by squamous epithelium and keratinocytes with amorphous material suggesting keratinization. They may occur congenitally or iatrogenically. In congenital cases, they are usually associated with spinal dysraphisms such as spina bifida, while iatrogenic cases are most often attributed to a history of lumbar puncture, often repeated.1 In a study from 1962, Manno et al. found that 41% of 90 patients developed iatrogenic epidermoid cysts which could be attributed to the implantation of epidermis.2 Some have speculated that the reduced incidence of iatrogenic epidermoid cysts in modern times is due to the widespread use of styletted needles. Even with styletted needles, iatrogenic epidermoid cysts have been reported to occur, especially in cases in which the stylet is ill-fitting or when the lumbar puncture is repeated.3,4 Epidermoid cysts are slow-growing lesions, such that the onset of symptoms after the initial lumbar puncture may take several years.2 Symptoms develop as the cyst grows and causes compression of the adjacent neurologic structures. Initial symptoms are usually non-specific.
2
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Patients may experience a dull and localized back pain, numbness or weakness of the lower extremities, and incontinence.5 Symptoms depend upon the location as well as the nerve roots which are compressed. On MRI, epidermoid cysts are typically isointense to the surrounding cerebrospinal fluid. The lesion is usually well defined and peripherally enhances with gadolinium administration, as seen in this case.6 DWI can help to distinguish epidermoid cysts from arachnoid cysts, with the former demonstrating diffusion restriction while the latter does not.7 However, a definitive diagnosis is made histologically, demonstrating a cyst wall composed of keratinizing stratified squamous epithelium.5 In symptomatic cases, laminectomy with surgical resection is the treatment of choice. In most cases, a gross total resection can be accomplished safely.8 Often, the epidermoid cyst is adherent to surrounding neural tissue, which would require less aggressive subtotal resection and the use of EMG and somatosensory evoked potentials (SSEPs) to ensure postoperative intact neurologic function. The SSEP of the lower extremity can detect the integrity of the cauda equina through L4 to S1, and the EMG is used to detect the external anal sphincter activity to ensure the integrity of the S2-S4 nerve roots.9 Gross total resection is facilitated by proper microsurgical technique and the use of an ultrasonic surgical aspirator for debulking.7,9 While uncommon, recurrence may occur in cases of subtotal resection. While gross total resection is possible in a majority of cases, the tendency of these tumors to be adherent to surrounding tissue can in some cases leave tumor tissue behind, increasing the likelihood of recurrence. There is at least one documented case of a recurrent epidermoid cyst which required repeat surgery and the placement of an Ommaya reservoir for continual drainage.7 Tumor regrowth typically takes years, and atypical hyperplasia is exceedingly rare, though it has been documented.10 Conclusion While spinal epidermoid cysts are rare, they may arise as congenital lesions or as complications after lumbar puncture. In this case, the patient had a remote history of lumbar puncture during work-up for meningitis as a child. As a complication of lumbar puncture, the formation of an epidermoid cyst can occur and is thought to be the result of implanted cutaneous tissue. Therefore, it is necessary, as in all cases working up a non-specific symptom, to obtain a comprehensive history from both the patient and the family. This case provides an illustration of the clinical, radiographic, intraoperative, and pathological findings consistent with an iatrogenic epidermoid cyst. References 1. McDonald JV, Klump TE. Intraspinal epidermoid tumors caused by lumbar puncture. Archives of neurology. 1986;43(9):936-939. 2. Manno NJ, Uihlein A, Kernohan JW. Intraspinal epidermoids. Journal of neurosurgery. 1962;19:754-765. 3. Issaivanan M, Cohen S, Mittler M, Johnson A, Edelman M, Redner A. Iatrogenic spinal epidermoid cyst after lumbar puncture using needles with stylet. Pediatric hematology and oncology. 2011;28(7):600-603.
3
117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
4. 5.
6.
7. 8. 9.
10.
Per H, Kumandas S, Gumus H, Yikilmaz A, Kurtsoy A. Iatrogenic epidermoid tumor: late complication of lumbar puncture. Journal of child neurology. 2007;22(3):332-336. Yin H, Zhang D, Wu Z, Zhou W, Xiao J. Surgery and outcomes of six patients with intradural epidermoid cysts in the lumbar spine. World journal of surgical oncology. 2014;12:50-50. Amato VG, Assietti R, Arienta C. Intramedullary epidermoid cyst: preoperative diagnosis and surgical management after MRI introduction. Case report and updating of the literature. Journal of neurosurgical sciences. 2002;46(3-4):122-126. Fleming C, Kaliaperumal C, O'Sullivan M. Recurrent intramedullary epidermoid cyst of conus medullaris. BMJ case reports. 2011;2011:bcr1120115090. Beechar VB, Zinn PO, Heck KA, et al. Spinal Epidermoid Tumors: Case Report and Review of the Literature. Neurospine. 2018;15(2):117-122. Liu H, Zhang JN, Zhu T. Microsurgical treatment of spinal epidermoid and dermoid cysts in the lumbosacral region. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. 2012;19(5):712-717. Li J, Qian M, Huang X, Zhao L, Yang X, Xiao J. Repeated recurrent epidermoid cyst with atypical hyperplasia: A case report and literature review. Medicine. 2017;96(49):e8950-e8950.
Figures Figure 1: Preoperative and postoperative imaging. A) Preoperative T1 weighted sagittal MRI with gadolinium of the lumbar spine demonstrating a peripherally enhancing lesion within the spinal canal. B) Preoperative T2 weighted sagittal MRI of the lumbar spine demonstrating cystic lesion located ventral to the thecal sac. C) Preoperative diffusion-weighted sagittal MRI demonstrating a diffusion restriction within the lesion. D) Immediate postoperative T1 weighted sagittal MRI with gadolinium demonstrating successful removal of cyst. E) Immediate postoperative T2 weighted sagittal MRI of the lumbar spine demonstrating successful removal of cyst. F) Preoperative T2 weighted axial MRI of the L4-L5 disc space demonstrating compression of the thecal sac. The cyst occupies most of the spinal canal. G) 6-month postoperative T1 weighted axial MRI with gadolinium of the L4-L5 disc space demonstrating successful removal of cyst. H) 6-month postoperative T2 weighted axial MRI of the L4-L5 disc space demonstrating successful removal of cyst. Figure 2: A) Keratinizing squamous epithelium of epidermoid cyst, with exfoliated keratin material into the cyst cavity. Hematoxylin and eosin stain, original magnification 100X. B) Rhomboid cholesterol crystals from interior of epidermoid cyst, touch preparation of unfixed specimen. Hematoxylin and eosin stain, original magnification 100X.
4
MRI-Magnetic Resonance Imaging DWI-Diffusion-weighted imaging EMG-electromyography SSEPs-somatosensory evoked potentials
The authors, Vicent Dodson, Neil Majmundar, Leroy Sharer, and John L. Gillick have no conflicts of interest to report in regards to the submission of this manuscript for World Neurosurgery.