CASE 11864 Published on 14.06.2014

A cause of seizure: intracranial dermoid cysts

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Ammor H, Addou O, Boujarnija H, Lamrani Y, Boubbou M, Maâroufi M, Kamaoui I, Tizniti S.

30000 Fes, Morocco;
Email:ammor_hicham@hotmail.com

Patient

19 years, male

Categories

Area of Interest Neuroradiology brain ; Imaging Technique CT

Procedure Diagnostic procedure ; Special Focus Pathology ;

Show more Show less

Download as PDF Print Show related cases Notify admin

Clinical History

A 19-year-old male patient presented to the emergencies with a history of 3 episodes of new onset seizures associated with cephalgia and photophobia in a subfebrile context.
On presentation, the patient had a normal neurological and cranial nerve examination.

Imaging Findings

Non-contrast brain CT revealed 3 frontal formations consisting of two components: a fatty density area and high calcic density area. These formations cause a small mass-effect on the brain midline structures. (Fig. 1)

Discussion

Intracranial dermoid cysts are rare, benign, slow-growing neoplasms and are believed to arise from ectopic ectodermal cell rests incorporated in the neural groove at the time of closure. [1]
They are not true neoplasms, as they expand through agglomeration of desquamation products and sebaceous secretions in a cystic cavity [2] rather than via cell division.
They are usually located at the cerebellopontine angle, cerebellar vermis, fourth ventricle, parasellar region, and frontal and frontotemporal cisternal spaces. [3-6].
The most common symptoms include headache (32%) and seizure (30%) and when they become particularly extensive, symptoms will be related to compression of neurologic and vascular structures and eventually producing cerebral hypertension [7].
Chemical meningitis arises in a high rate of patients after rupture of the cyst. Malignant degeneration with developement of squamous cell carcinoma is uncommon but possible [8].
CT images show a uniloculated, well-delineated, cystic mass which has internal density characteristics consistent with fat (negative Hounsfield units), and hyperdense calcifications in the wall.
It rarely enhances after injection of contrast media [9-11].
On MRI, dermoid cysts are hyperintense on T1WI and heterogenous on T2WI; Typically, it can be recognized on FSE T2WI sequence lines in hyposignal inside the cystic lesion (corresponding to hair contained in the cyst). FatSat sequence can confirm the lipid presence into the lesion. The 3D chemical shift selective sequences can be used to increase specificity of the diagnostic [12, 13].
After injection of contrast media, minimal enhancement of capsule exists without central enhancement. [7]
When a dermoid cyst ruptures, fat droplets (which are hypodense on CT or T1 hyperintense on MRI) may be seen disseminated and floating within the nondependent parts of the ventricular system and/or subarachnoid space [14].
Dermoid cysts are benign formations, and have a generally good prognosis. Surgical treatment is only indicated when dermoid cysts cause mass effect and serious neurological deficits.
If the cyst is intact, the objective is complete surgical elimination of the capsule and intracystic constituent and dissection from adjacent neurovascular structures [2, 15].

Differential Diagnosis List

Intracranial dermoid cysts

Epidermoid cyst

Intracranial lipoma

Final Diagnosis

Intracranial dermoid cysts

References

[1] El-Bahy K, Kotb A, Galal A,et al (2006) Ruptured intracranial dermoid cysts. Acta Neurochir (Wien) 148:457–62 (PMID: 16437187)

[2] Yasargil MG, Abernathey CD, Sarioglu AC (1989) Microneurosurgical treatment of intracranial dermoid and epidermoid tumors. Neurosurgery 24(4):561-567 (PMID: 2710301)

[3] Conley FK (1996) Epidermoid and dermoid tumors: Clinical features and surgical management, in Wilkins RH, Setti SR (eds). Neurosurgery, ed 2, vol I. New York, The McGraw-Hill pp 971–976

[4] Osborn GA (1994) Miscellaneous tumors, cysts, and metastasis,in Osborn GA (ed). Diagnostic Neuroradiology. St Louis, Mosby-Year Book pp 626–670

[5] Stendel R, Pietila TA, Lehmann K, Kurth R, Suess O, Brock M (2002) Ruptured intracranial dermoid cysts. Surg Neurol 57: 391–398 (PMID: 12176198)

[6] Wilms G, Casselman J, Demaerel P, Plets C, De Haene I, Baert AL (1991) CT and MRI of ruptured intracranial dermoids. Neuroradiology 33: 149–151 (PMID: 2046900)

[7] Alessandro D\'Amore, Alessandro Borderi, Rita Chiaramonte, Giorgio Conte, Ignazio Chiaramonte, and Vincenzo Albanese (2013) CT and MR Studies of Giant Dermoid Cyst Associated to Fat Dissemination at the Cortical and Cisternal Cerebral Spaces. Case Reports in Radiology vol. 2013, Article ID 239258, 5 pages (PMID: 23401832)

[8] P. Lunardi, P. Missori, A. Rizzo, and F. M. Gagliardi (1989) Chemical meningitis in ruptured intracranial dermoid. Case report and review of the literature. Surgical Neurology vol. 32, no. 6, pp.449–452 (PMID: 2700053)

[9] Stephenson TF, Spitzer RM (1987) MR and CT appearance of ruptured intracranial dermoid tumors. Comput Radiol 11(5-6):249-251. (PMID: 3436130)

[10] Hamer J (1980) Diagnosis by computerized tomography of intradural dermoid with spontaneous rupture of the cyst. Acta Neurochir (Wien) 51(3-4):219-226. (PMID: 7368996)

[11] Jamjoom AB, Cummins BH (1989) The diagnosis of ruptured intracranial dermoid cysts. Br J Neurosurg 3(5):609 -612 (PMID: 2818854)

[12] A. G. Osborn and M. T. Preece (2006) Intracranial cysts: radiologicpathologic correlation and imaging approach. Radiology vol. 239, no. 3, pp. 650–664. (PMID: 16714456)

[13] D. R. Warakaulle and P. Anslow (2003) Differential diagnosis of intracranial lesions with high signal on T1 or low signal on T2-weighted MRI. Clinical Radiology vol. 58, no. 12, pp. 922–933. (PMID: 14654024)

[14] M. Jordan Ray, MD, David W. Barnett, MD, George J. Snipes, MD, Kennith F. Layton, MD, and Michael J. Opatowsky, MD (2012) Ruptured intracranial dermoid cyst. Proc (Bayl Univ Med Cent) 25(1):23–25. (PMID: 22275778)

[15] Lunardi P, Missori P (1991) Supratentorial dermoid cysts. J Neurosurg 75(2):262-266 (PMID: 2072164)

Case information

URL:	https://www.eurorad.org/case/11864
DOI:	10.1594/EURORAD/CASE.11864
ISSN:	1563-4086

Figure 1

Brain CT

NECT of the brain: 3 frontal formations consisting of two components: a fatty density area and high calcic density area (arrows). These formations cause a small mass-effect on the brain midline structures.