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Middle fossa epidermoid cyst

Case series

Three operations described were performed through an approximately 2-cm diameter temporal craniotomy after a straight skin incision was made. Resection was then performed under the magnification of a 30-degree rigid endoscope, which mandated the use of exclusively conventional microsurgical instruments.

Total resection was accomplished in all three patients with large middle fossa epidermoid cysts through a small temporal corticectomy, without damage to neurovascular structures.

This procedure allowed the association of a smaller craniotomy, better cosmetic results, and minor retraction of the brain to wide resection of the tumor and satisfactory functional outcomes 1).

Case reports


A 50-year-old man presented with a rare giant crossing cranium-temporal combined epidermal cyst. Physical examination found left facial numbness and temple severely numbness with light pressure. Horizontalis craniocerebral computed tomography demonstrated a mass lesion of 3.0 × 2.0 cm in the middle cranial fossa area; sagittal craniocerebral magnetic resonance scanning demonstrated a mass consisting of 2 leaves (the upper one, 4.0 × 3.0 cm; the lower one, 2.0 × 1.5 cm). Computed tomography angiography showed that the blood supply of the lesion came from superficial temporal artery and middle cranial fossa artery. The clinical diagnosis was neurilemmoma. Surgery revealed a pearly cyst consisting of 2 leaves (connected by a narrowed bridge located at the articular fossa of temporal bone) was 6 × 3 × 3 cm. Histologic examination disclosed disintegrated keratinizing epithelium layer, keratinizing epithelium layer, and stratified squamous epithelium layer from inner to outer and found no hair follicles or sebaceous gland with the diagnosis of epidermoid cyst. Surgery was successfully performed, and the patient was discharged home with severer left facial numbness relatively and left jaw slight opening. The present case suggests that epidermoid cysts can be seen in any location, even giant crossing cranium-temporal combined lesion, and the blood supply should be considered as a factor judging its pathogenesis 2).


You et al. present the first case of ectopic ventricular recurrence of an epidermoid cyst in the middle fossa with confirming histological characteristics. A 51-year-old woman presented with an epidermoid cyst in the middle fossa and underwent complete resection. On the 6-month surgical follow-up MRI, a nodular lesion was detected in the frontal horn of the left lateral ventricle without evidence of recurrence at the primary site. The patient underwent transcortial tumor resection. Results of histological studies confirmed that the lesion was an epidermoid cyst similar to the primary lesion. This is a case report of the cerebrospinal fluid spread of an epidermoid cyst, which strengthens the case for special care at the time of surgery to prevent spread of the lesion 3).


Inoue et al. report an unusual case of an intracranial, interdural epidermoid tumor and cyst in a 72-year-old woman who presented with longstanding, mild numbness over her right cheek. She was initially treated conservatively, but on follow-up review the mass was found to have grown and evidence of hemorrhage was present, and therefore a subtotal resection was performed. This case should probably be classified as a paratrigeminal, interdural epidermoid cyst; this is the first known report in which magnetic resonance and computerized tomography images of such an entity are presented and discussed 4).


Kobayashi et al. report the case of a 51-year-old female suffering from generalized convulsions. Having fallen into a semicoma due to the convulsions, she was referred to our department on August 5, 1992. Neurological examination revealed slight dementia but no other deficits. The tumor was mainly located in the temporal lobe but communicated with the CSF space of C-P angle through a narrow channel shown on MRI. She underwent an operation for tumor removal and left the hospital with no neurological deficits. Several cases of intracranial intramedullary epidermoid have been reported in the literature, but none of them proved to be completely intramedullary. On operation or on CT and MRI, all of them were shown to communicate with the CSF space. The possible occurrence of an epidermoid from medullary substance was discussed 5).

Trivelato FP, Giannetti AV. Endoscope-controlled microneurosurgery to treat middle fossa epidermoid cysts: technical case report. Neurosurgery. 2008 Mar;62(3 Suppl 1):105-6; discussion106-7. doi: 10.1227/01.neu.0000317379.60938.1f. PubMed PMID: 18424973.
Yang T, Zhang L, Bao H, Hua Z. Rare giant epidermal cyst in the infratemporal fossa and middle cranial fossa. J Craniofac Surg. 2012 Jul;23(4):e334-6. doi: 10.1097/SCS.0b013e3182564a87. PubMed PMID: 22801171.
You NK, Ahn JY, Hong CK, Lee KS. Ectopic ventricular recurrence of an epidermoid cyst in the middle fossa. J Clin Neurosci. 2008 May;15(5):578-80. doi: 10.1016/j.jocn.2007.02.010. Epub 2008 Mar 4. PubMed PMID: 18313302.
Inoue Y, Ohata K, Nakayama K, Haba T, Shakudo M. An unusual middle fossa interdural epidermoid tumor. Case report. J Neurosurg. 2001 Nov;95(5):902-4. PubMed PMID: 11702885.
Kobayashi E, Serizawa T, Mitsuhashi H. [A case report of giant epidermoid in the temporal lobe: considerations of the occurrence of intramedullary epidermoids]. No Shinkei Geka. 1994 Aug;22(8):769-73. Review. Japanese. PubMed PMID: 8072636.
middle_fossa_epidermoid_cyst.txt · Last modified: 2015/11/23 11:17 (external edit)