.
This commit is contained in:
Ross
@@ -0,0 +1,446 @@
|
||||
---
|
||||
title: "Epidermoid Cyst"
|
||||
docid: "704c5ddf-e1f7-4a5d-a1b8-5b0e603170d9"
|
||||
authors:
|
||||
- key: "5cff4116-3654-4b3a-bb75-5ebe0b8c9850"
|
||||
value: "Anne G. Osborn, MD, FACR"
|
||||
breadcrumbs:
|
||||
-
|
||||
name: "Brain"
|
||||
slug: "brain"
|
||||
treeNodeId: "6d8829f1-14d7-45af-8675-255189aa526a"
|
||||
-
|
||||
name: "Diagnosis"
|
||||
slug: "diagnosis"
|
||||
treeNodeId: "51c00394-446e-4a38-94af-d3b1d14d34e8"
|
||||
-
|
||||
name: "Pathology-Based Diagnoses"
|
||||
slug: "pathology-based-diagnoses"
|
||||
treeNodeId: "d9d3a8ed-f21b-4831-8c77-591a3500ef77"
|
||||
-
|
||||
name: "Primary Nonneoplastic Cysts"
|
||||
slug: "primary-nonneoplastic-cysts"
|
||||
treeNodeId: "8037bffe-f61e-4433-b841-a263bcfbe056"
|
||||
-
|
||||
name: "Epidermoid Cyst"
|
||||
slug: "epidermoid-cyst"
|
||||
treeNodeId: null
|
||||
category: "Brain"
|
||||
documentVersionId: "4092685b-a22f-42ca-b14b-6a21122b651f"
|
||||
imageCount: 22
|
||||
lastUpdated: "06/12/20"
|
||||
pageDescription: "Epidermoid Cyst"
|
||||
pageKeywords: "Brain, Diagnosis, Pathology-Based Diagnoses, Primary Nonneoplastic Cysts, Epidermoid Cyst"
|
||||
pageTitle: "Epidermoid Cyst | STATdx"
|
||||
enhancedTitle: "Epidermoid Cyst"
|
||||
type: "DX"
|
||||
references: true
|
||||
breadcrumbs:
|
||||
- "Brain"
|
||||
- "Diagnosis"
|
||||
- "Pathology-Based Diagnoses"
|
||||
- "Primary Nonneoplastic Cysts"
|
||||
- "Epidermoid Cyst"
|
||||
---
|
||||
# KEY FACTS
|
||||
|
||||
- ## Terminology
|
||||
|
||||
|
||||
- Intracranial epidermoids ("pearly" tumor)
|
||||
- Congenital ectodermal inclusion cysts, not true neoplasm
|
||||
- ## Imaging
|
||||
|
||||
|
||||
- CSF-like mass that insinuates cisterns and encases neurovascular structures
|
||||
- Morphology: Lobulated, irregular, cauliflower-like mass with "fronds"
|
||||
- FLAIR: Usually does not completely null
|
||||
- DWI: Diffusion restriction definitively distinguishes from arachnoid cyst
|
||||
- ## Top Differential Diagnoses
|
||||
|
||||
|
||||
- Arachnoid cyst
|
||||
- Inflammatory cyst (i.e., neurocysticercosis)
|
||||
- Cystic neoplasm
|
||||
- Dermoid cyst
|
||||
- ## Pathology
|
||||
|
||||
|
||||
- Arise from ectodermal inclusions during neural tube closure, 3rd to 5th week of embryogenesis
|
||||
- ## Clinical Issues
|
||||
|
||||
|
||||
- Symptoms depend on location and effect on adjacent neurovascular structures
|
||||
- Most common symptom: Headache
|
||||
- Cranial nerves V, VII, VIII neuropathy common
|
||||
- 0.2-1.8% of all primary intracranial tumors
|
||||
- Rare malignant degeneration into squamous cell carcinoma
|
||||
- Treatment: Microsurgical resection
|
||||
- Recurrence common if incompletely removed
|
||||
- ## Diagnostic Checklist
|
||||
|
||||
|
||||
- Insinuates CSF spaces, surrounds arteries, CNs with minimal displacement
|
||||
- Incomplete nulling on FLAIR; DWI hyperintense
|
||||
|
||||
# TERMINOLOGY
|
||||
|
||||
- ## Synonyms
|
||||
|
||||
|
||||
- Ectodermal inclusion cyst
|
||||
- "Pearly" tumor
|
||||
- ## Definitions
|
||||
|
||||
|
||||
- Intracranial epidermoids are congenital inclusion cysts (not "tumors")
|
||||
- Benign, slow-growing congenital lesions derived from ectodermal remnants sequestrated during embryogenesis
|
||||
|
||||
# IMAGING
|
||||
|
||||
- ## General Features
|
||||
|
||||
|
||||
- ### Best diagnostic clue
|
||||
|
||||
|
||||
- CSF-like mass that insinuates cisterns and encases neurovascular structures
|
||||
- ### Location
|
||||
|
||||
|
||||
- Intradural (90%), strong predilection for basal cisterns
|
||||
- Cerebellopontine angle (CPA) (40-50%)
|
||||
- 4th ventricle (17%)
|
||||
- Parasellar/middle cranial fossa/sylvian fissure (10-15%)
|
||||
- Parenchymal (i.e., cerebral hemispheres) rare (1.5%)
|
||||
- Brainstem exceedingly rare
|
||||
- Extradural (10%)
|
||||
- Skull (intradiploic within frontal, parietal, occipital, sphenoid skull) as well as spine
|
||||
- ### Size
|
||||
|
||||
|
||||
- Variable; extradural intradiploic variants can become huge with minimal/no neurologic deficits
|
||||
- Grow slowly by desquamation of normal cells into cystic cavity
|
||||
- ### Morphology
|
||||
|
||||
|
||||
- Lobulated, irregular, cauliflower-like excrescences
|
||||
- Insinuates without mass effect unless large
|
||||
- ## Radiographic Findings
|
||||
|
||||
|
||||
- ### Radiography
|
||||
|
||||
|
||||
- Diploic space epidermoids
|
||||
- May alter scalp, outer/inner skull tables, and epidural space appearance
|
||||
- Typically round or lobulated
|
||||
- Well delineated with sclerotic rim
|
||||
- ## CT Findings
|
||||
|
||||
|
||||
- ### NECT
|
||||
|
||||
|
||||
- Round/lobulated mass
|
||||
- > 95% hypodense, resembling CSF
|
||||
- 10-25% contain calcifications
|
||||
- Rare variant = "dense" epidermoid
|
||||
- 3% of intracranial epidermoids
|
||||
- Secondary to hemorrhage, high protein, saponification of cyst debris to calcium soaps or iron-containing pigment
|
||||
- ### CECT
|
||||
|
||||
|
||||
- Usually none, though margin of cyst may show minimal enhancement
|
||||
- ### Bone CT
|
||||
|
||||
|
||||
- May have bony erosion; sharply corticated margins when intradiploic
|
||||
- ## MR Findings
|
||||
|
||||
|
||||
- ### T1WI
|
||||
|
||||
|
||||
- Often (~ 75%) slightly hyperintense to CSF
|
||||
- Lobulated periphery may be slightly more hyperintense than center
|
||||
- Uncommonly hyperintense to brain ("white epidermoid") due to high triglycerides and unsaturated fatty acids
|
||||
- Uncommonly hypointense to CSF ("black epidermoid")
|
||||
- Presence of solid crystal cholesterol and keratin
|
||||
- Lack of triglycerides and unsaturated fatty acids
|
||||
- ### T2WI
|
||||
|
||||
|
||||
- Often isointense (65%) to slightly hyperintense (35%) to CSF
|
||||
- Very rarely hypointense due to calcification, ↓ hydration, viscous secretions, and iron pigments
|
||||
- ### FLAIR
|
||||
|
||||
|
||||
- Usually does not completely null
|
||||
- ### DWI
|
||||
|
||||
|
||||
- Characteristic hyperintensity
|
||||
- High fractional anisotropy due to diffusion along 2D geometric plane
|
||||
- Attributed to microstructure of parallel-layered keratin filaments and flakes
|
||||
- In comparison to white matter, which also shows high fractional anisotropy, due to diffusion along single direction
|
||||
- ADC = brain parenchyma
|
||||
- ### T1WI C+
|
||||
|
||||
|
||||
- Usually none, though margin of cyst may show minimal enhancement (25%)
|
||||
- Enhancing tumor is sign of malignant degeneration
|
||||
- ### MRS
|
||||
|
||||
|
||||
- Resonances from lactate
|
||||
- No NAA, choline, or lipid
|
||||
- ## Angiographic Findings
|
||||
|
||||
|
||||
- Conventional
|
||||
- Depending on location and size, may show avascular mass effect
|
||||
- ## Nonvascular Interventions
|
||||
|
||||
|
||||
- ### Myelography
|
||||
|
||||
|
||||
- Cisternography contrast delineates irregular lobulated tumor borders, extends into interstices
|
||||
- ## Imaging Recommendations
|
||||
|
||||
|
||||
- ### Best imaging tool
|
||||
|
||||
|
||||
- MR
|
||||
- ### Protocol advice
|
||||
|
||||
|
||||
- FLAIR will often distinguish, whereas conventional sequences may not
|
||||
- Diffusion restriction definitively distinguishes from arachnoid cyst
|
||||
|
||||
# DIFFERENTIAL DIAGNOSIS
|
||||
|
||||
- [Arachnoid Cyst](/document/arachnoid-cyst/d25aaeb3-5b3c-4483-99dc-2757468eedb9)
|
||||
- Usually isointense to CSF on all standard sequences
|
||||
- Completely nulls on FLAIR
|
||||
- Hypointense diffusion: Contains highly mobile CSF, ADC = stationary water
|
||||
- Rather than insinuate and engulf local structures, arachnoid cysts displace them
|
||||
- Smooth surface, unlike lobulations of epidermoids
|
||||
- [Inflammatory Cyst](/document/neurocysticercosis/6a45835f-6d7c-443e-874a-f33131d3def1)
|
||||
- i.e., neurocysticercosis
|
||||
- Often enhances
|
||||
- Density/signal intensity usually not precisely like CSF
|
||||
- Adjacent edema, gliosis common
|
||||
- [Cystic Neoplasm](/document/pilocytic-astrocytoma/7eca92f5-6caa-4300-9afe-1b733b4473b2)
|
||||
- Attenuation/signal intensity not that of CSF
|
||||
- Often enhances
|
||||
- [Dermoid Cyst](/document/dermoid-cyst/9b7aeb04-2cb3-405d-8c51-dd13297dd67c)
|
||||
- Usually at or near midline
|
||||
- Resembles fat, not CSF, and contains dermal appendages; often ruptured
|
||||
|
||||
# PATHOLOGY
|
||||
|
||||
- ## General Features
|
||||
|
||||
|
||||
- ### Etiology
|
||||
|
||||
|
||||
- Congenital: Embryology
|
||||
- Arise from ectodermal inclusions during neural tube closure, 3rd to 5th week of embryogenesis
|
||||
- Congenital intradural CPA epidermoids derived from cells of 1st branchial groove
|
||||
- Acquired: Develop as result of trauma
|
||||
- Uncommon etiology for intracranial tumors
|
||||
- More common as spine etiology following LP
|
||||
- ### Genetics
|
||||
|
||||
|
||||
- Sporadic
|
||||
- ### Associated abnormalities
|
||||
|
||||
|
||||
- May have occipital/nasofrontal dermal sinus tract
|
||||
- ## Gross Pathologic & Surgical Features
|
||||
|
||||
|
||||
- Outer surface often has shiny, glistening, mother-of-pearl appearance ("beautiful tumor")
|
||||
- Soft and pliable
|
||||
- Conforms to shape of adjacent local structures/spaces
|
||||
- Lobulated excrescences
|
||||
- May invaginate into brain
|
||||
- Insinuating growth pattern, extends through cisterns, surrounds and encases vessels/nerves
|
||||
- Cyst filled with soft, waxy, creamy, or flaky keratinaceous material
|
||||
- ## Microscopic Features
|
||||
|
||||
|
||||
- Cyst wall = internal layer of simple stratified cuboidal squamous epithelium covered by fibrous capsule
|
||||
- Cyst contents = solid crystalline cholesterol, keratinaceous debris; no dermal appendages
|
||||
- Grows by progressive desquamation with conversion to keratin/cholesterol crystals, forming concentric lamellae
|
||||
|
||||
# CLINICAL ISSUES
|
||||
|
||||
- ## Presentation
|
||||
|
||||
|
||||
- ### Most common signs/symptoms
|
||||
|
||||
|
||||
- Symptoms depend on location and effect on adjacent neurovascular structures
|
||||
- Most common symptom: Headache
|
||||
- Cranial nerves V, VII, VIII neuropathy common
|
||||
- 4th ventricular cerebellar signs common, yet increased intracranial pressure rare
|
||||
- Less commonly hypopituitarism, diabetes insipidus
|
||||
- Seizures if in sylvian fissure/temporal lobe
|
||||
- May remain clinically silent for many years
|
||||
- ## Demographics
|
||||
|
||||
|
||||
- ### Age
|
||||
|
||||
|
||||
- Presents between 20-60 years with peak at 40 years
|
||||
- Presentation is uncommon in childhood
|
||||
- ### Sex
|
||||
|
||||
|
||||
- M = F
|
||||
- CT hyperdense variant lesions have female predominance (M:F = 1:2.5)
|
||||
- ### Epidemiology
|
||||
|
||||
|
||||
- Epidermoids make up 0.2-1.8% of all primary intracranial tumors
|
||||
- Much more common than dermoid cyst (4-9x higher incidence)
|
||||
- Most common congenital intracranial tumor
|
||||
- 3rd most common CPA/IAC mass, after vestibular schwannoma and meningioma
|
||||
- ## Natural History & Prognosis
|
||||
|
||||
|
||||
- Grows slowly: Epithelial component growth rate commensurate to that of normal epithelium
|
||||
- Chemical meningitis possible from content leakage
|
||||
- Rare malignant degeneration into squamous cell carcinoma (SCCa) reported
|
||||
- Postulated prolonged or reparative process from foreign material leads to cellular atypia and neoplasia
|
||||
- Often predated by frequent recurrences
|
||||
- May occur years after surgical resection
|
||||
- Mean age at presentation: 52 years with male preponderance
|
||||
- ## Treatment
|
||||
|
||||
|
||||
- Microsurgical resection
|
||||
- Complicated by investment of local structures
|
||||
- Recurrence common if cyst capsule incompletely removed
|
||||
- Subarachnoid dissemination of contents may occur during operative/postoperative course
|
||||
- May cause chemical meningitis
|
||||
- CSF seeding and implantation reported
|
||||
- Rare malignant degeneration of resection bed into SCCa reported
|
||||
|
||||
# DIAGNOSTIC CHECKLIST
|
||||
|
||||
- ## Consider
|
||||
|
||||
|
||||
- Epidermoid if insinuates CSF spaces, surrounds arteries/CNs with minimal displacement
|
||||
- ## Image Interpretation Pearls
|
||||
|
||||
|
||||
- Resembles CSF on imaging studies, except usually incomplete nulling on FLAIR
|
||||
- DWI hyperintensity is diagnostic
|
||||
|
||||
da5731a9-6c09-4bf5-99d9-fdefe09d5800
|
||||
|
||||
## References
|
||||
|
||||
# Selected References
|
||||
|
||||
1. [Pons Escoda A et al: Imaging of skull vault tumors in adults. Insights Imaging. 11(1):23, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32056014%5Bpmid%5D)
|
||||
1. [Bobeff EJ et al: Suprasellar Epidermoid Cyst: Case Report of Extended Endoscopic Transsphenoidal Resection and Systematic Review of the Literature. World Neurosurg. 128:514-26, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31121364%5Bpmid%5D)
|
||||
1. [Hitti FL et al: Endoscopic Resection of a Cerebellopontine Angle Epidermoid Cyst via a Retrosigmoid Approach. J Neurol Surg B Skull Base. 80(Suppl 3):S330, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31143618%5Bpmid%5D)
|
||||
1. [Ma J et al: Primary intradiploic epidermoid cyst: a case report with literature review. Clin Neuropathol. 38(1):28-32, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30526818%5Bpmid%5D)
|
||||
1. [Badat N et al: Malignant transformation of epidermoid cyst with diffuse leptomeningeal carcinomatosis on skull base and trigeminal perineural spread. J Neuroradiol. 45(5):337-40, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30036548%5Bpmid%5D)
|
||||
1. [Gollapudi PR et al: A frontal giant intradiploic giant pearl (epidermoid cyst) with intracranial and extracranial extension: a rare entity. J Pediatr Neurosci. 13(4):480-2, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30937095%5Bpmid%5D)
|
||||
1. [Twede JV et al: Intraosseous epidermoid cyst of the skull: case study and radiological imaging considerations. Dermatol Online J. 24(7), 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=30261578%5Bpmid%5D)
|
||||
1. [Vaz-Guimaraes F et al: Endoscopic endonasal surgery for epidermoid and dermoid cysts: a 10-year experience. J Neurosurg. 1-11, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29547084%5Bpmid%5D)
|
||||
1. [Aboud E et al: Giant intracranial epidermoids: is total removal feasible? J Neurosurg. 1-14, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25594324%5Bpmid%5D)
|
||||
1. [Law EK et al: Atypical intracranial epidermoid cysts: rare anomalies with unique radiological features. Case Rep Radiol. 2015:528632, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25667778%5Bpmid%5D)
|
||||
1. [Demir MK et al: Rare and challenging extra-axial brain lesions: CT and MRI findings with clinico-radiological differential diagnosis and pathological correlation. Diagn Interv Radiol. 20(5):448-52, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=25010368%5Bpmid%5D)
|
||||
1. [Vellutini EA et al: Malignant transformation of intracranial epidermoid cyst. Br J Neurosurg. 28(4):507-9, 2014](http://www.ncbi.nlm.nih.gov/pubmed/?term=24345076%5Bpmid%5D)
|
||||
1. [Velamati R et al: Meningitis secondary to ruptured epidermoid cyst: case-based review. Pediatr Ann. 42(6):248-51, 2013](http://www.ncbi.nlm.nih.gov/pubmed/?term=23718247%5Bpmid%5D)
|
||||
1. [Ren X et al: Clinical, radiological, and pathological features of 24 atypical intracranial epidermoid cysts. J Neurosurg. 116(3):611-21, 2012](http://www.ncbi.nlm.nih.gov/pubmed/?term=22175719%5Bpmid%5D)
|
||||
1. [Li F et al: Hyperdense intracranial epidermoid cysts: a study of 15 cases. Acta Neurochir (Wien). 149(1):31-9; discussion 39, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17151831%5Bpmid%5D)
|
||||
|
||||
|
||||
## Images
|
||||
|
||||
|
||||
### Selected Images
|
||||
|
||||
|
||||
*Sagittal graphic shows a multilobulated epidermoid primarily within the prepontine cistern. Significant mass effect displaces the pons, cervicomedullary junction, and upper cervical spine.*
|
||||
|
||||
|
||||
*Gross pathology shows an epidermoid cyst extending anterosuperiorly from the cerebellopontine angle (CPA) cistern, insinuating within the prepontine cistern and encasing the basilar artery <img src='img/arrows/BO.png'/>. Note its typical pearly appearance. (Courtesy E. Hedley-Whyte, MD.)*
|
||||
|
||||
|
||||
*Axial NECT shows a typical epidermoid cyst (EC) in an expanded right CPA cistern. Note that the EC <img src='img/arrows/WS.png'/> is slightly more dense than the adjacent CSF <img src='img/arrows/WC.png'/> and has a frothy, cauliflower-like surface.*
|
||||
|
||||
|
||||
*MR shows CPA epidermoid cyst that resembles CSF on T1 and T2 <img src='img/arrows/WS.png'/> but typically does not suppress on FLAIR <img src='img/arrows/BO.png'/> and demonstrates moderate restricted diffusion <img src='img/arrows/WO.png'/>.*
|
||||
|
||||
|
||||
*Sagittal T1 MR in a 39-year-old woman with a history of attempted resection of a posterior fossa EC shows a large mass infiltrating the prepontine cistern <img src='img/arrows/BO.png'/> and wrapping around the cervicomedullary junction <img src='img/arrows/WC.png'/>. The mass is nearly isointense with CSF.*
|
||||
|
||||
|
||||
*Axial PD MR in the same patient shows a lobulated mass <img src='img/arrows/BS.png'/> in the right CPA cistern that is nearly isointense with CSF in the cistern and 4th ventricle <img src='img/arrows/BO.png'/>.*
|
||||
|
||||
|
||||
*Axial T2 MR in the same patient shows the mass <img src='img/arrows/WS.png'/> is nearly as hyperintense as fluid in the CPA cistern and 4th ventricle <img src='img/arrows/WO.png'/>.*
|
||||
|
||||
|
||||
*Coronal T2 MR shows the lobulated, hyperintense mass <img src='img/arrows/WS.png'/> encases and displaces the basilar artery <img src='img/arrows/WO.png'/>. CSF in the right middle fossa <img src='img/arrows/WC.png'/> is a cavity from prior attempted resection.*
|
||||
|
||||
|
||||
*Axial FLAIR MR demonstrates that the lobulated, cauliflower-like mass <img src='img/arrows/WS.png'/> in the right CPA and prepontine cistern does not suppress.*
|
||||
|
||||
|
||||
*The mass <img src='img/arrows/WS.png'/> restricts on DWI MR. This is a classic EC that infiltrates and insinuates CSF cisterns, encasing vessels (like the basilar artery) and cranial nerves (in this case, cranial nerves VII and VIII).*
|
||||
|
||||
|
||||
### Additional Images
|
||||
|
||||
|
||||
*Gross pathology nicely shows the typical shiny, glistening, pearly appearance of an epidermoid residing within the prepontine cistern, which was also encasing the basilar artery (not shown).*
|
||||
|
||||
|
||||
*Axial T2 MR shows a nearly CSF isointense epidermoid within the left anterior middle cranial fossa.*
|
||||
|
||||
|
||||
*Axial DWI MR shows restricted diffusion within a left anterior middle cranial fossa epidermoid.*
|
||||
|
||||
|
||||
*Axial T2 MR shows an extraaxial left occipital mass that scallops the skull <img src='img/arrows/WO.png'/> and displaces the dura inwardly <img src='img/arrows/WS.png'/>.*
|
||||
|
||||
|
||||
*Axial T1 C+ FS MR in the same patient shows the mass does not enhance <img src='img/arrows/WS.png'/>. DWI (not shown) clinched the diagnosis as an EC. This is an atypical location for epidermoid.*
|
||||
|
||||
|
||||
*Axial bone CT in the same patient reveals significant yet benign-appearing remodeling and scalloping of the inner calvarial table <img src='img/arrows/WO.png'/>.*
|
||||
|
||||
|
||||
*Bone CT in a 16-year-old girl with nonspecific headaches shows a smoothly marginated, lytic, expansile mass <img src='img/arrows/WC.png'/> centered on the diploic space of the calvarium.*
|
||||
|
||||
|
||||
*Axial NECT in the same patient shows the calvarial cyst is hypodense relative to cortex. This is a classic EC of the skull and was an incidental finding in this asymptomatic patient.*
|
||||
|
||||
|
||||
*Axial bone CT demonstrates the typical appearance of a large intradiploic epidermoid as an expansile lesion with sharply corticated margins <img src='img/arrows/BS.png'/>.*
|
||||
|
||||
|
||||
*Axial T2 MR in the same patient shows the lobulated, hyperintense mass scallops the skull <img src='img/arrows/WS.png'/>. Intradiploic EC was removed at surgery.*
|
||||
|
||||
|
||||
*Axial T1 (upper left), T2 (upper right) and FLAIR (lower left) MR show an extensive intradiploid EC. Coronal T1 C+ MR (lower right) shows mild enhancement <img src='img/arrows/WS.png'/> around the cyst margin.*
|
||||
|
||||
|
||||
*Axial T2 (upper left), FLAIR (upper right), T1 C+ (lower left), and DWI (lower right) MR show a recurrent EC that appears intraaxial, but the original surgery 24 years prior disclosed an EC of the quadrigeminal cistern.*
|
||||
|
||||
Reference in New Issue
Block a user