Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
Year : 2014  |  Volume : 10  |  Issue : 4  |  Page : 1098-1100

Large oculomotor nerve schwannoma - Rare entity: A case report with review of literature

1 Department of Radiation Oncology, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India
2 Department of Pathology, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India

Date of Web Publication9-Jan-2015

Correspondence Address:
L Pavan Kumar
Department of Radiation Oncology, Nizam's Institute of medical Sciences, Hyderabad - 500 082, Telangana
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0973-1482.146111

Rights and Permissions
 > Abstract 

Schwannomas commonly arise from peripheral nerves. Intracranial schwannomas are comparatively rare and are seen commonly as vestibular tumors. Oculomotor nerve schwannomas are extremely rare tumors, these are usually symptomatic. A 29 year aged male presented with diplopia and blurring of vision in left eye and found to have an extra-axial lesion at left cavernous sinus involving oculomotor nerve. The excised tumor showed classic morphology of a schwannoma. Postoperatively patient developed complete oculomotor nerve palsy. The tumor recurred after 2 years. It was re-excised followed by radiotherapy.

 > Abstract in Chinese 





Keywords: Oculomotor nerve schwannoma, radiation therapy, cranial nerve schwannoma

How to cite this article:
Kumar L P, Monica I, Uppin MS, Kotiyala V J. Large oculomotor nerve schwannoma - Rare entity: A case report with review of literature. J Can Res Ther 2014;10:1098-100

How to cite this URL:
Kumar L P, Monica I, Uppin MS, Kotiyala V J. Large oculomotor nerve schwannoma - Rare entity: A case report with review of literature. J Can Res Ther [serial online] 2014 [cited 2020 Jul 13];10:1098-100. Available from: http://www.cancerjournal.net/text.asp?2014/10/4/1098/146111

 > Introduction Top

Schwannomas commonly arise from peripheral nerves. Intracranial schwannomas are comparatively rare and are seen commonly as vestibular tumors. Among nonvestibular schwannomas, trigeminal nerve involvement is common followed by glossopharyngeal, vagal, facial, accessory, hypoglossal, oculomotor, trochlear, and abducens nerve schwannomas, in descending order of frequency. II and V nerve involvement is reported common in neurofibromatosis 2. [1] Oculomotor nerve schwannomas are extremely rare tumors, these are usually symptomatic. At present, there is no standard treatment for these tumors. In this case report, we highlight a large sporadic oculomotor schwannoma in a 29-year-old patient.

 > Case report Top

A 29 years aged male presented with diplopia and blurring of vision in left eye of 2 months duration. Examination revealed impaired extraocular movements - up going, down gage and intorsion in left eye, right eye was normal, no other neurological deficit was noted. According to Snellen's chart patients, visual acuity was 6/60. Magnetic resonance imaging (MRI) plain and contrast showed a 3 cm × 2.5 cm × 3 cm well defined, extra-axial lesion at left cavernous sinus lateral wall extending into middle cranial fossa, isointense on T1 and T2, suggestive of giant oculomotor schwannoma [Figure 1]. Patient underwent left orbitozygomatic craniotomy, intraoperatively tumor was protruding superiorly and laterally from cavernous sins, cystic portion decompressed by giving incision over dura lateral to oculomotor the nerve on superior wall of cavernous sinus. Tumor was soft suckable, moderately vascular and arising from the oculomotor nerve before its entry into oculomotor cistern. Near total excision of the tumor was done.
Figure 1: Magnetic resonance imaging brain postcontrast T1 image showing well defined intensely enhancing, extra-axial lobulated lesion situated posterior to the left orbit apex

Click here to view

Postoperative histology showed lesion composed of hypercellular (Antoni A) and hypocellular areas (Antoni B). The hypercellular areas are composed of spindle cells with elongated nuclei arranged in fascicles. Nuclear palisading with verocay bodies was present. Hypocellular areas show loose network of cells in a myxoid background. Thickened and hyalinized vessels are seen. There was no evidence of atypical mitosis or necrosis. These features were consistent with a diagnosis of schwannoma [Figure 2]. The cells showed strong immunohistochemical positivity for S100.
Figure 2: (a) Lesion composed of spindle-shaped cells arranged in hypercellular (Antoni A) and hypocellular areas (Antoni B) with elongated vesicular nuclei and buckling of nuclei. (b) Interspersed hyalinized thickened blood vessels

Click here to view

Postoperatively patient developed complete oculomotor nerve palsy leading to restricted eyeball movements, and complete ptosis left eye. Two years following the surgery, patient came back with diminished vision in the right eye and headache. On examination he had complete ptosis of left eye, visual acuity in right eye - counting finger at 3 m, left eye - counting finger at 1 m distance, left eye oculomotor nerve palsy was present. MRI showed large extra-axial lesion involving left parasellar, medial temporal and basifrontal region measuring 5.5 cm × 5.5 cm × 6.9 cm in size. It was hypointense on T1 and heterogeneous on T2 with mass effect suggesting recurrence of the tumor [Figure 3]. He underwent reexploration, intraoperatively large extra-axial tumor with both cystic and solid component noted and subtotal excision of the tumor was done.
Figure 3: Two-year postoperative magnetic resonance imaging image showing intensely enhancing lesion t the same site with multiple nonenhancing hypointense areas within it

Click here to view

Postoperative histology was similar to that described with first excision. Postoperative radiotherapy was given to residual disease on a linear accelerator by three-dimensional radiotherapy 2 Gy/fraction to a total dose of 54 Gy.

 > Discussion Top

Schwannomas arise from Schwann cells of the myelin sheath of the peripheral nerve. Schwannomas constitute 7% of all intracranial neoplasms. [2] These may be sporadic or hereditary. Sporadic schwannomas are usually unilateral and common in the fourth or fifth decade of life. Hereditary schwannomas usually develop in second or third decade of life. These tumors are usually well circumscribed, grow in an expansible fashion, displacing the adjacent structures rather than invading them.

The majority of schwannomas arise from cranial nerve VIII (CN VIII) (vestibulocochlear nerve) and less commonly from CN V (trigeminal nerve), other CNs involvement are very rare. Schwannomas of the oculomotor nerve are extrememly rare. Celli et al.; divided oculomotor nerve schwannomas into three groups; cisternal, cisternocavernous and cavernous lesions. [3] This classification based on the preferred extension of these tumors. Oculomotor nerve schwannomas are most often in the interpeduncular cistern and less often in the cavernous sinus or orbit.

In our literature review we found that approximately 33 cases of well-documented oculomotor nerve schwannomas are reported in the literature, of which 12 cases are larger than 2.5 cm in diameter and largest measuring 5.5 cm in diameter. [4] Now we are reporting the case of oculomotor nerve schwannoma measuring 6.9 cm in diameter and will be the largest case in the literature to document till date.

Clinical manifestations

Duration of symptoms before diagnosis are typically shorter than for other group of schwannomas, averaging 9-13 months. Most common presenting symptoms are diplopia and headache, other symptoms include visual loss due to compression of the optic nerve. [5]


Differential diagnosis of oculomotor schwannoma would include, parasellar or sellar lesions involving cavernous sinus, like meningioma which appears homogenous, hyperdense with hyperostosis of adjacent bones on plain computed tomography (CT) with an intense uniform enhancement contrast-enhanced CT and may calcify (25%). On MRI the lesion is isointense on T1-weighted, hyperintense on T2-weighted and will show rapid enhancement, with enhancing dural tail on contrast administration or pituitary macroadenoma, with lateral extension into cavernous sinus showing mixed signal intensity with uniform enhancement on MRI and is associated with enlarged sella turcica, supra-sellar extension, and diaphragmatic constriction.

Occulomotor schwannoma is difficult to differential from cisternal trochlear or trigeminal Schwannoma. Partially thrombosed aneurysm which will show variable signal on T1-weighted and T2-weighted sequences due to blood products in different stages of clot evolution.

Lymphoma and metastasis often involve adjacent bone with replacement of fatty bone marrow, with soft tissue of decreased signal intensity. Lymphoma often also shows leptomeningeal spread.

Para-midline chordomas are rare and are markedly hyperintense on T2-weighted sequences. [6]

Pathological features

Morphology and IHC

The histopathology showed characteristic features of the tumor with Antoni A and Antoni B areas. Nuclear palisading and verrcoy bodies were identified. There was mild cellular pleomorphism however mitosis was not seen. Immunohistochemistry with S-100 showed intense positivity within the tumor cells, and Ki-67 index was <1%.


These rare tumors are many options in their management. Very small lesions detected incidentally can be observed, symptomatic lesions can be managed with surgery or radiation therapy. A very high-incidence of complete oculomotor nerve palsy was reported in the literature after radical surgery, hence, a near total excision followed by radiotherapy provides a safer alternative compared to radical surgery. [7]

 > References Top

Fisher LM, Doherty JK, Lev MH, Slattery WH 3 rd . Distribution of nonvestibular cranial nerve schwannomas in neurofibromatosis 2. Otol Neurotol 2007;28:1083-90.  Back to cited text no. 1
Newton HB. Primary brain tumors: Review of etiology, diagnosis and treatment. Am Fam Physician 1994;49:787-97.  Back to cited text no. 2
Celli P, Ferrante L, Acqui M, Mastronardi L, Fortuna A, Palma L. Neurinoma of the third, fourth, and sixth cranial nerves: A survey and report of a new fourth nerve case. Surg Neurol 1992;38:216-24.  Back to cited text no. 3
Prabhu SS, Bruner JM. Large oculomotor schwannoma presenting as a parasellar mass: A case report and literature review. Surg Neurol Int 2010;1:15.  Back to cited text no. 4
[PUBMED]  Medknow Journal  
Mehta VS, Singh RV, Misra NK, Choudhary C. Schwannoma of the oculomotor nerve. Br J Neurosurg 1990;4:69-72.  Back to cited text no. 5
Osborn AG. Brain tumors and tumor like masses: Classification and differential diagnosis. Diagnostic Neuroradiology. Ch. 12, 1 st ed.: Elsevier; 1994. p. 498-505.  Back to cited text no. 6
Saetia K, Larbcharoensub N, Wetchagama N. Oculomotor nerve schwannoma: A case report and review of the literature. J Med Assoc Thai 2011;94:1002-7.  Back to cited text no. 7


  [Figure 1], [Figure 2], [Figure 3]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  >Abstract>Introduction>Case report>Discussion>Article Figures
  In this article

 Article Access Statistics
    PDF Downloaded147    
    Comments [Add]    

Recommend this journal