We are sharing multiple cases of epidermoids.
The diagnosis was formulated on the basis of MRI.
MRI appears to be the modality of choice for radiological evaluation of epidermoids.
Typically epidermoid tumors return signals similar to fluid i-e are hypointense on T1-weighted and hyperintense on T2-weighted images.
No post-contrast enhancement is noted due to low vascularity. Fluid-Attenuated Inversion Recovery (FLAIR) sequences help distinguish them from similar-appearing arachnoid cysts,
as the former are hyperintense.
But the key sequence is DWI.
Diffusion-weighted images further enhance the accuracy of preoperative diagnosis. Calcifications may be seen within these tumors in 10%–25% of cases.
Case 1: 35 year old male presented in the outpatient clinic with history of trauma 20 years back.
He had a complaint of headache.
The headaches were mild to moderate in intensity and were improved with over-the-counter analgesics. The patient underwent Magnetic Resonance Imaging (MRI),
which revealed a mass lesion of about 2.5 x 1.7 cm in dimension,
located in occipital horn of left lateral ventricle.
The lesion was producing homogenous hypointense signals on T1-weighted images(Fig.1),
hyperintense on T2-weighted images(Fig.2).
There was diffusion restriction(Fig.3) and no post-gadolinium enhancement of the lesion (Fig.4).
The above findings were suggestive of an epidermoid cyst.
Fig. 1: 35 years old man with history of trauma and headache; T1WI show cystic lesion in occipital horn of left lateral ventricle.
Fig. 2: Same patient, Minimally expansile lesion in occipital horn left lateral ventricle with CSF signals i-e hyperintense on T2WI.
Fig. 3: Same patient, no post contrast enhancement is noted.
Fig. 4: Same patient, diffusion restriction seen in the lesion
Case 2: 34 year old male presented in the outpatient clinic with history of sudden off and on aattacks of syncope.
He had a complaint of vertigo and hypotension too. The patient underwent Magnetic Resonance Imaging (MRI),
which revealed a mass lesion of about 4.9 x 3.9 cm in dimension,
located in rhomboid fossa in fourth ventricle.
The lesion was producing homogenous hypointense signals on T1-weighted images(Fig.5),
hyperintense on T2-weighted images(Fig.6).
There was diffusion restriction(Fig.7&8) and no post-gadolinium enhancement of the lesion (Fig.9).
The epidermoid was producing compression to the flow of CSF at the level of fourth ventricle.
Fig. 5: 34 year old man with syncope; T1W hypointense area in fourth ventricle
Fig. 6: 34 year old man with syncope; T2W hyperintense area in fourth ventricle
Fig. 7: 34 year old man with syncope; diffusion restriction is seen in fourth ventricle
Fig. 8: 34 year old man with syncope; diffusion restriction is seen in fourth ventricle
Fig. 9: 34 year old man with syncope; heterogenous FLAIR signals in fourth ventricle
Case 3: 30 year old female presented in the eye outpatient clinic with history of swelling along lateral aspect of left eye since birth.
It is non-tender.
The MRI revealed an epidermoid with CSF signals on T1& T2WI(Fig.10 & 11), with diffusion restriction(Fig.13) and no post-gadolinium enhancement of the lesion (Fig.12).
Fig. 10: 30 year old man with swelling lateral aspect of left eye since birth; hypointense T1W signals are appreciated.
Fig. 11: same patient; hyperintense T2W signals lateral canthus left eye
Fig. 12: Same patient, no enhancement is seen on post gadolinium T1WI.
Fig. 13: Same patient, diffusion restriction is seen on DWI
Case 4: 33 year old male with history of swelling on right side at the back of scalp since child hood.
MRI revealed well defind extra axial abnormal signal intensity mass lesion with an extra cranial component.
It appears hyperintense on T1WI(Fig.16) and FLAIR.
It is hyperintense on T2WI(Fig.
15).
It shows diffusion restriction on DWI (Fig.
17).
It was operated and was confirmed to be an epidermoid.
Fig. 15: 33 year old patient with extra axial intracranial epidermoid hyperintense on T2WI.
Fig. 16: 33 year old patient with extra axial intracranial epidermoid hypointense on T1WI.
Fig. 17: 33 year old patient with extra axial intracranial epidermoid shows diffusion restriction on DWI.
Case 5:15 year old boy with off and on visual symptoms.
He underwent MRI which showed abnormal signal intensity area in the region of basal cisterns with ill defined margins(Fig.18).
It was hyperintense on T2WI(Fig.19) and heterogenous on FLAIR images(Fig.
20).
It showed diffusion restriction on DWI(Fig.21) and appears low on ADC mapping(Fig.
22).
It was found to be an epidermoid.
Fig. 18: 15 years old patient with ill defined Hypointense area on T1WI
Fig. 19: 15 years old patient with ill defined Hyperintense area on T2WI
Fig. 20: 15 years old patient with ill defined heterogenous area on FLAIR
Fig. 21: 15 years old patient with ill defined area in basal cisterns which shows diffusion restriction
Fig. 22: 15 years old patient with ill defined area in basal cisterns which shows diffusion restriction and appears low on ADC mapping
Case 6: 10 year old girl with frontal headache off and on.
She underwent MRI which showed abnormal signal intensity area in the frontal interhemispheric region with ill defined margins,
hypointense on T1WI(Fig.24).
It was hyperintense on T2WI(Fig.23) and heterogenous on FLAIR images(Fig.
25).
It showed diffusion restriction on DWI(Fig.26).
It was found to be an epidermoid.
Fig. 23: 10 year old girl with history of frontal headache shows T2W hyperintense area in interhemispheric frontal region
Fig. 24: same patient, same lesion appears hypointense on T1WI
Fig. 25: Same lesion appears heterogenous on FLAIR images
Fig. 26: Same lesion shows diffusion restriction on DWI