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|LETTER TO EDITOR
|Year : 2020 | Volume
| Issue : 3 | Page : 713-715
Invasive Medial Temporal Pilocytic Glioma
Rajesh K Meena, Ramesh S Doddamani, Kanwaljeet Garg, Dipanshu Narula, Deepak Agrawal
Department of Neurosurgery and Gamma Knife Center, All India Institute of Medical Sciences, AIIMS, New Delhi, India
|Date of Web Publication||6-Jul-2020|
Dr. Rajesh K Meena
Department of Neurosurgery and Gamma Knife Center, All India Institute of Medical Sciences, Room No. 720, CN Centre, AIIMS, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Meena RK, Doddamani RS, Garg K, Narula D, Agrawal D. Invasive Medial Temporal Pilocytic Glioma. Neurol India 2020;68:713-5
Gliomas are characterized by their infiltrative growth pattern and migration along white matter fiber tracts, leading to diffuse growth and involvement of adjacent gyrus. As pia-mater and arachnoid act as a solid barrier, extension of hemispheric gliomas outside the limits of brain tissue is extremely rare. However, cases of gliomas that have a core in the nervous tissue, but grow outside the anatomical boundaries of the brain within adjacent subarachnoid spaces have been reported in the literature. These gliomas are traditionally known as exophytic gliomas. Only two case reports of exophytic gliomas arising in the medial temporal lobe exist in the English literature to the best of our knowledge., Both of them were high-grade gliomas. We report a rare case of medial temporal pilocytic astrocytoma that extended extensively beyond its anatomical limits to be aptly called as “Giant exophytic medial temporal glioma.”
A 20-year-old female landed up in the emergency department of our institute with an episode of generalized tonic-clonic seizure. She also had complaints of progressively increasing holocranial headache from the last three years and left-sided visual blurring from last six months. Neurological examination revealed mild papilledema with vision in the left eye 6/60 on Snellen chart. Her tone and reflexes on left side of the body were increased with a left hemiparesis of grade 4/5. Patient was optimized and plain CT of the head was done which showed a hypo-dense lesion in the skull base extending to the sellar/supra-sellar region and posterior fossa [Figure 1]. Contrast MRI of the brain showed a well-defined lobulated T2 hyper-intense lesion measuring approximately 5.7 × 4.6 cm in the right medial temporal lobe, extending into peri-mesencephalic and pre-pontine cistern medially and causing mass effect over cerebral peduncle. The lesion was homogeneously hypo-intense on T1-weighted images and showed partial suppression of signal in FLAIR images [Figure 2]. Post contrast imaging showed intense irregular solid enhancement [Figure 3]. No evidence of diffusion restriction or hemorrhage was noted. Radiological differential diagnosis of optico-chiasmatic glioma, Pleomorphic Xantho-astrocytoma, or Ganglio-glioma were considered prior to surgery.
|Figure 1: Non-contrast computed tomography scan of the patient showing a hypo-dense lesion in the skull base|
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|Figure 2: Magnetic resonance imaging of the patient (a) T1-weighted, (b) T2- weighted, and (c) Fluid attenuated inversion recovery images of the patient|
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|Figure 3: Contrast-enhanced magnetic resonance imaging of the patient (a) axial, (b) sagittal, and (c) coronal views|
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Surgical excision of the lesion was done via right pterional craniotomy. Tumor was grayish-white in color, showed variegated consistency, mildly vascular, partially suckable, seen arising from the right medial temporal lobe. Near total excision of tumor could be achieved capsulated portion adherent to the major cerebral arteries and perforators being left behind.
Postoperative period was uneventful except partial third nerve paresis on the left side that recovered over two weeks. Histopathology showed a pilocytic astrocytoma with MIB-1 index of 2% in the highest proliferative area. Immunohistochemistry for p53 was negative.
Gliomas with an extensive subarachnoid spread are rarely reported in the literature.,,,, Moreover, this feature is common in high-grade gliomas. Two cases of exophytic temporal glioma with extension into the basal cisterns have been reported in the literature., Tanka et al. reported a temporal anaplastic glioma with encasement of third cranial nerve and local extension to the basal cisterns. Similarly, Kros et al. reported a case of right temporal GBM with orbital and subarachnoid tumor invasion. However, both these tumors are high-grade gliomas. In our case, pilocytic astrocytoma of the medial temporal lobe showed exophytic component with extensive extension into subarachnoid space and basal cistern that has not been previously reported in the literature. Velasquez et al. in a study of insular gliomas with exophytic extension to the Sylvian cistern reported that low-grade gliomas can also be capable of exophytic extension. In our case, probably, medial temporal glioma by unknown mechanism has developed the ability to invade pia- and arachnoid locally and further extending to the sphenoidal compartment of the Sylvian cistern. As these compartments communicate medially with the carotid cistern, tumor cells can invade and proliferate medially into the basal cisterns. Once in the basal cisterns, tumor cells can proliferate rapidly as basal cisterns offer the least resistance pathway for tumor cell to spread as seen in our case.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]