A 65-year-old female presented with difficulty in speech and was found to have left eye ptosis, tongue deviation to the right, and reduced strength in the right shoulder. Imaging showed an irregular hypodense lesion extending from the left sylvian fissure displacing the MCA inferiorly, with scattered fat droplets in the subarachnoid spaces. This was diagnosed as a ruptured epidermoid cyst based on imaging characteristics. Epidermoid cysts are congenital lesions that typically present in middle age due to mass effect. They appear hypodense on CT resembling CSF and have increased signal on DWI, helping differentiate them from arachnoid cysts. Treatment is surgical excision though complete removal

1. Dr.I.Gurubharath MD PhD Dr.Muthu Saravanan MD

2. HISTORY
 65 year old female presented to the ER with
complaints of difficulty in speech since morning after
waking up from bed.
 No history of limb weakness/regurgitation of
food/seizures/LOC/Urinary incontinence.
 No history of similar illness in the past.
 Known case of diabetes mellitus and hypertension .

3. GENERAL EXAMINATION
On Examination,
 The patient was conscious ,Oriented ,Afebrile
 Pulse – 78/min
 BP - 154/94 mmhg
 CVS - S1,S2 present
 RS – B/L NVBS
 P/A – Soft

4. CNS
 Higher motor functions were normal
 Dysarthria is present
 Left eye ptosis present
 Left nasolabial fold appears less prominent
 Tongue appears deviated to right side
 Uvula appears deviated to left side
 Shrugging of shoulder on right side is of reduced power
 Motor examination:
RIGHT LEFT
•POWER
UL
LL
5/5
5/5
5/5
5/5
•TONE Normal Normal
•PLANTAR Mute Mute

5. CLINICAL DIAGNOSIS
 ? Mono-neuritis multiplex with involvement of CraniaI
Nerves IX,X,XI and XII.

6. CT IMAGING

7. • An ill-defined, irregular, extra-axial hypodense fat containing lesion (-35 to -60 HU)
extending from left sylvian fissure to slightly right above the suprasellar region.

8. • Scattered fat containing droplets were disseminated throughout the subarachnoid
spaces into both sylvian fissures and basal cisterns.
• Lesion appears to displace the left MCA inferiorly.

9. • Calcification is noted surrounding the lesion.
• Bilateral basal ganglia calcification noted.

10. MR IMAGING

11. T1WI
• Iso intense to CSF with higher signal around periphery.
• Scattered fat droplets are seen disseminated throughout the subarachnoid spaces
into both sylvian fissures and basal cistern .

12. T2WI & FLAIR
• Slightly hyperintense to CSF on T2.
• Heterogeneous/dirty signal; higher than CSF on FLAIR.

13. DWI
• Increased signal on DWI

14. DWI ADC
• Acute infarct noted in the left centrum semiovale and corona radiata

15. DDX
The differential to be considered are:
 Epidermoid cyst
 Hypodense on CT
 Heterogeneous signal on FLAIR
 Increased signal on DWI
 CSF collections, e.g. Arachnoid cyst or Mega cisterna
magna
 Less lobulated
 Follows CSF on all sequences, including FLAIR and DWI
 Dermoid cyst
 Often fat density due to sebum
 Typically located along the midline

16.  Inflammatory cyst, e.g. Neurocysticercosis
 smaller, but may be multiple
 may enhance peripherally
 may have associated oedema
 usually no restricted diffusion
 Cystic tumours, e.g. Acoustic
schwannoma or Craniopharyngioma
 a solid enhancing component is usually identifiable.

17. RADIOLOGICAL DIAGNOSIS
Ruptured epidermoid cyst

18. DISCUSSION

19. INTRACRANIAL EPIDERMOID CYSTS
 Intracranial epidermoid cysts are relatively
common congenital lesions which account for about
1% of all intracranial tumours.
 Third most common CPA mass, after vestibular
schwannoma & meningioma
 Typically present in middle age due to mass effect on
adjacent structures.

20. ETIOLOGY
 Congenital:
 Arise from ectodermal inclusions during neural tube closure
 Acquired:
 Develop as a result of trauma
 Uncommon etiology for intracranial lesion
 More common as spine etiology following LP

21. CLINICAL PRESENTATION
 Signs and symptoms of epidermoid cysts are due to
gradual mass effect, with presentation including:
 Headaches: most common
 Cranial nerve deficits
 Cerebellar symptoms
 Seizures
 Raised intracranial pressure

22. LOCATION
 Intradural: 90%
 Cerebellopontine angle: 40-50%
 Suprasellar cistern: 10-15%
 Fourth ventricle: ~17%
 Middle cranial fossa
 Interhemispheric: < 5%
 Spinal (rare)
 Extradural: 10%
 most within skull

23. RADIOLOGICAL FEATURES
 Intracranial epidermoid cysts appear as lobulated lesions
that fill and expand CSF spaces and exert a gradual mass
effect on the adjacent nerves and vessels.
 Their contents mimic CSF on CT.
 Epidermoids are often indistinguishable from arachnoid
cysts or dilated CSF spaces on many MR sequences,
except for DWI/ADC which helps to differentiate them.

24. CT
NECT
 Round/lobulated mass
 > 95% hypodense,
resembling CSF
 10-25% present with
calcifications.
CECT
 Usually none, although
margin of cyst may show
minimal enhancement

25.  Rare variant :
“Dense" epidermoid
 rarely an epidermoid cyst
may be hyperdense due to
haemorrhage,
saponification or high
protein content ("white
epidermoids").

26. MRI
T1WI
 Usually isointense to CSF
 Higher signal compared to
CSF around the periphery
of the lesion is frequently
seen
 Rare intralesional
haemorrhage can also
result in intrinsic high
signal

27. T2WI
 Usually isointense to CSF
(65%)
 Slightly hyperintense (35%)

28. FLAIR
 Often heterogeneous/dirty
signal; higher than CSF

29. DWI
 Increased signal intensity
 Useful for differentiation
from arachnoid cysts and
other dilated CSF spaces.

30. TREATMENT AND PROGNOSIS
EPIDERMOID CYST
RUPTURED EPIDERMOID
CYST
 Surgical excision is the treatment
of choice if symptomatic.
 However, complete resection is
difficult as not all tissue can be
removed, especially from around
cranial nerves and vessels.
 Recurrence can occur, although
growth is typically slow and many
years can elapse without new
symptoms.
 Prognosis is usually good.
 Treatment is with steroids and
antibiotics to relieve symptoms
and combined with surgical
resection
 Lumbar drainage is done for cases
with dissemination into the CSF
pathway.

31. THANK YOU