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Table of Contents    
Year : 2014  |  Volume : 62  |  Issue : 1  |  Page : 103-104

Pearly encirclement of the brainstem

Department of Neurosurgery, Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Parel, Mumbai, Maharashtra, India

Date of Submission14-Jan-2014
Date of Decision15-Jan-2014
Date of Acceptance26-Jan-2014
Date of Web Publication7-Mar-2014

Correspondence Address:
Raghvendra Ramdasi
Department of Neurosurgery, Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Parel, Mumbai, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.128357

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How to cite this article:
Ramdasi R, Chagla A, Mahore A. Pearly encirclement of the brainstem. Neurol India 2014;62:103-4

How to cite this URL:
Ramdasi R, Chagla A, Mahore A. Pearly encirclement of the brainstem. Neurol India [serial online] 2014 [cited 2022 Aug 7];62:103-4. Available from: https://www.neurologyindia.com/text.asp?2014/62/1/103/128357


A 21-year-old female patient presented with headache of 4 months and imbalance on walking of 4 months duration. Neurological examination revealed bilateral cerebellar signs, more on the left side. Magnetic resonance imaging (MRI) brain showed a lesion in the fourth ventricle extending to both cerebello-pontine angle and encircling the brainstem. The lesion was hypointense on T1-weighted, hyperintense on T2-weighted images [Figure 1]a-c with restricted diffusion on diffusion weighted imaging [Figure 1]d. The patient underwent surgery via midline sub occipital telovelar approach. The cyst was completely filling the fourth ventricle, cisterna magna and extending to the both cerebello-pontine angle, prepontine cisterns through both foramina of Lushka. The brainstem was relatively shifted to the right side. The lesion was also extending into right cerebello-pontine angle via right foramen of Lushka completing the circle [Figure 2]a which was not evident on the MRI. The lesion was removed piecemeal from either side of basilar artery through the path created by lesion itself to achieve complete excision [Figure 2]b and c. The cyst was completely excised except few capsular fragments densely adherent to nerves and vessels. Post-operative course was uneventful. Histopathological examination revealed cyst lined by stratified squamous epithelium with lamellated keratin consistent with epidermoid cyst [Figure 1]d. At follow-up patient has improvement in neurological condition.
Figure 1: (a and b) represent axial and sagittal plain T1-weighted magnetic resonance images respectively showing hypointense lesion in the fourth ventricle extending to left cerebello-pontine angle and encircling the brainstem. (c) T2-weighted image where the lesion is hyperintense and engulfs basilar artery. The lesion restricts diffusion on diffusion weighted image (d)

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Figure 2: (a and b) represent intraoperative photographs of the lesion in which (a) lesion fi lling the fourth ventricle displacing the brainstem towards left. The lesion extending to right foramen of Lushka also seen in it (b) complete excision of the lesion and baring of basilar artery (c) post-operative T2-weighted axial magnetic resonance imaging revealing
complete excision of the lesion. (d) The photomicrograph of the lesion (H and E, ×100) showing stratifi ed squamous lining epithelium with lamellated keratin

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Epidermoid cysts also called "pearly tumors" constitute about 1% of all intracranial primary tumors and in 16% of these are found in the fourth ventricle. [1],[2] Despite of this fact, very few cases of fourth ventricular epidermoids extending to cerebello-pontine angle have been described and epidermoids encircling the brainstem as in our case has never been described. [2] These rarely cause hydrocephalus due to the persistence of CSF flow spaces between the capsule and the walls of the ventricle. Hence unlike other fourth ventricular tumors these acquire a considerable size before producing symptoms. [1] The space created by these slowly expanding lesions aids in reaching the otherwise inaccessible areas. Thus, epidermoids fall in the hole dig by themselves. Epidermoid encircling the brainstem is a unique neurosurgical challenge. Maximum safe resection may be achieved by piecemeal excision through bilateral telovelar routes following the natural passages used by the lesion.

  References Top

1.Oulali N, Moufid F, Ghailan MR, Hosni B. Epidermoid cyst of the cisterna magna and fourth ventricle. Pan Afr Med J 2012;13:19.  Back to cited text no. 1
2.Tancredi A, Fiume D, Gazzeri G. Epidermoid cysts of the fourth ventricle: Very long follow up in 9 cases and review of the literature.Acta Neurochir (Wien) 2003;145:905-10.  Back to cited text no. 2


  [Figure 1], [Figure 2]


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