Figure 1
Axial T1 w image
On axial T1 weighted image, a well defined lobulated predominantly hyperintense lesion is seen across the extra-axial right cerebellopontine cistern.
White epedermoid - a case report
SectionNeuroradiology
Case TypeClinical Cases
AuthorsChethan Belgur S , Yugandhara M Shah
Connected authors
32 years, male
Clinical History
A male patient aged 32 years presented with history of dizziness and vertigo for one year.
Imaging Findings
On axial T1weighted image a well defined lobulated iso intense to predominantly hyperintense extra axial lesion is seen with its epicenter across the right cerebello-pontine region and crossing the midline through the prepontine cistern and occupying the left cerebello-pontine cistern. The crossing over is also demonstrated on coronal T1 FS image. On The axial T1 weighted contrast enhanced image the lesion does not show enhancement. This lesion also demonstrates diffusion restriction on diffusion weighted image.
Discussion
Epidermoid cysts are also referred to as “pearly tumours”. [2]
Epidermoid cysts are congenital ectodermal inclusion cysts formed during neural tube closure in the 3rd–5th week of embryogenesis and comprise approximately 0.2 to 1.8 % of primary intracranial tumours. The most common location of epidermoid is the cerebello-pontine cistern. [1]
The microscopic cyst lining consists of stratified squamous epithelium. The outer layer is collagenous connective tissue. Cystic contents usually include debris, keratin, water, and cholesterol laid down in a lamellar fashion. Epidermoid cysts do not contain dermal appendages. [1]
On CT: Most of the epidermoid cysts are well-defined lobulated hypoattenuated masses that resemble CSF and do not enhance. Calcifications can be seen in 10 to 25% of cases. [1] The white epidermoid appear as hyperattenauted cysts on CT. [1]
On MRI: The MR appearance of the epidermoid cyst typically depends on the chemical composition of the intracystic contents which includes cholesterol, keratin and calcium. [4]
Most of the epidermoid cysts show slight hyperintense signal as compared to the CSF on both the T1 and T2 weighted images. They do not show suppression on the T2 W FLAIR images. Most of them do not show any contrast enhancement except for some cases in which a minimal rim of enhancement occurs. [1]
The rare white epidermoids are seen as bright signal intensity on T1 weighted images and the high signal intensity is contributed to high protein content. [1] "White epidermoids" show reversed signal intensity on MRI, with high signal intensity on T1WI and low signal intensity on T2WI. [5]
Malignant transformation of an epidermoid cyst into a squamous cell carcinoma is a known but extremely rare occurrence. Malignant transformation is suggested by enhancement after contrast administration or rapid growth. [3]
Epidermoid cysts are congenital ectodermal inclusion cysts formed during neural tube closure in the 3rd–5th week of embryogenesis and comprise approximately 0.2 to 1.8 % of primary intracranial tumours. The most common location of epidermoid is the cerebello-pontine cistern. [1]
The microscopic cyst lining consists of stratified squamous epithelium. The outer layer is collagenous connective tissue. Cystic contents usually include debris, keratin, water, and cholesterol laid down in a lamellar fashion. Epidermoid cysts do not contain dermal appendages. [1]
On CT: Most of the epidermoid cysts are well-defined lobulated hypoattenuated masses that resemble CSF and do not enhance. Calcifications can be seen in 10 to 25% of cases. [1] The white epidermoid appear as hyperattenauted cysts on CT. [1]
On MRI: The MR appearance of the epidermoid cyst typically depends on the chemical composition of the intracystic contents which includes cholesterol, keratin and calcium. [4]
Most of the epidermoid cysts show slight hyperintense signal as compared to the CSF on both the T1 and T2 weighted images. They do not show suppression on the T2 W FLAIR images. Most of them do not show any contrast enhancement except for some cases in which a minimal rim of enhancement occurs. [1]
The rare white epidermoids are seen as bright signal intensity on T1 weighted images and the high signal intensity is contributed to high protein content. [1] "White epidermoids" show reversed signal intensity on MRI, with high signal intensity on T1WI and low signal intensity on T2WI. [5]
Malignant transformation of an epidermoid cyst into a squamous cell carcinoma is a known but extremely rare occurrence. Malignant transformation is suggested by enhancement after contrast administration or rapid growth. [3]
Differential Diagnosis List
White epidermoid cyst
Arachnoid cyst
Dermoid cyst
Final Diagnosis
White epidermoid cyst
References
[1] Anne G. Osborn, MD, Michael T. Preece, MD (2006) Intracranial Cysts: RadiologicPathologic Correlation and Imaging Approach. Radiology Volume 239: Number 3
[2] Peter Kalina, MD; Karen Black, MD; Rona Woldenberg, MD: (1997) Epidermoid. Applied Radiology , Journals Volume 26, Number 6
[3] K. Mermuys, G. Wilms, Ph. Demaerel, (2008) Epidermoid cyst of the fourth ventricle: diffusion-weighted and flair MR imaging findings. JBR–BTR, 91: 58-60 (PMID: 18549150)
[4] Batuk Diyora, Naren Nayak, Dhananjay Kale, Hanmant Kamble, and Alok Sharma : (2010) Frontal intraparenchymal “White epidermoid cyst”: A rare occurrence,. J Neurosci Rural Pract 1(2): 125–127. doi: 10.4103/0976-3147.71735 (PMID: 21808524)
[5] Puranik A, Sankhe S, Goel N, Mahore A (2012) Cerebral shading sign in a giant intraparenchymal white epidermoid. Neurol India 60:265-6 (PMID: 22626729)
Case information
| URL: | https://www.eurorad.org/case/11041 |
| DOI: | 10.1594/EURORAD/CASE.11041 |
| ISSN: | 1563-4086 |
Figure 2
Axial T1 w image 2
On axial T1 weighted image, a well defined lobulated iso to predominantly hyperintense lesion located across the right cerebello-pontine cistern and crossing the midline to occupy the left cerebellopontine cistern through the prepontine cistern.
Figure 3
Coronal T1 w fat saturated image 1
On the coronal T1 weighted fat suppressed image, the isointense to hyperintense extra axial lesion demonstrates well defined lobulated contour. Also note that the hyperintense areas within the lesion are not suppressed on this image.
On the coronal T1 weighted fat suppressed image, the isointense to hyperintense extra-axial lesion shows extension into left CP angle cistern.
Figure 5
Axial T1 w contrast image
On T1 weighted axial contrast enhanced image, the lesion does not demonstrate contrast enhancement. The hyperintense areas seen within the lesion on T1 weighted contrast image are also seen on precontrast T1 weighted image.
Axial T1 w image
On axial T1 weighted image, a well defined lobulated predominantly hyperintense lesion is seen across the extra-axial right cerebellopontine cistern.
DM WIMS Dept of radiology and imaging
DM WIMS Dept of radiology and imaging
Axial T1 w image 2
On axial T1 weighted image, a well defined lobulated iso to predominantly hyperintense lesion located across the right cerebello-pontine cistern and crossing the midline to occupy the left cerebellopontine cistern through the prepontine cistern.
DM WIMS Dept of radiology and imaging
DM WIMS Dept of radiology and imaging
Coronal T1 w fat saturated image 1
On the coronal T1 weighted fat suppressed image, the isointense to hyperintense extra axial lesion demonstrates well defined lobulated contour. Also note that the hyperintense areas within the lesion are not suppressed on this image.
DM WIMS Dept of radiology and imaging
DM WIMS Dept of radiology and imaging
On the coronal T1 weighted fat suppressed image, the isointense to hyperintense extra-axial lesion shows extension into left CP angle cistern.
DM WIMS Dept of radiology and imaging
DM WIMS Dept of radiology and imaging
Axial T1 w contrast image
On T1 weighted axial contrast enhanced image, the lesion does not demonstrate contrast enhancement. The hyperintense areas seen within the lesion on T1 weighted contrast image are also seen on precontrast T1 weighted image.
DM WIMS Dept of radiology and imaging
DM WIMS Dept of radiology and imaging