Neurol India Home 
 

CASE REPORT
Year : 2014  |  Volume : 62  |  Issue : 4  |  Page : 429--431

Olfactory schwannoma: A report of two cases and literature review

Zheng Wang1, Wei Zhang1, Gan You1, Jiangfei Wang1, Guilin Li2, Zhixian Gao1, Jian Xie1, Zheng Wang1, Wei Zhang1, Gan You1, Jiangfei Wang1, Guilin Li2, Zhixian Gao1, Jian Xie1,  
1 Department of Neurosurgery, Beijing Tiantan Hospital, Beijing; Beijing Institute for Brain Disorders Brain Tumor Center, Beijing 100050, China
2 Department of Neuropathology, Beijing Neurosurgical Institute, Capital Medical University; Beijing Institute for Brain Disorders Brain Tumor Center, Beijing 100050, China

Correspondence Address:
Jian Xie
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, No. 6 Tiantan Xili, Dongcheng District, Beijing 100 050
China
Jian Xie
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, No. 6 Tiantan Xili, Dongcheng District, Beijing 100 050
China

Abstract

Intracranial schwannoma is a kind of benign intracranial tumors, derived from neuron myelin sheath, growing slowly and curable. Olfactory schwannoma is an exceedingly rare kind of schwannoma, whose origin is still uncovered. Although several theories have been put up for pathogenesis of olfactory schwannoma, till now, none of these hypotheses has been widely accepted and acknowledged officially. Up to date, only 46 cases of olfactory schwannoma were reported across numerous institutes worldwide. Here we gathered two cases from Department of Neurosurgery in Beijing Tiantan Hospital across two years collection.



How to cite this article:
Wang Z, Zhang W, You G, Wang J, Li G, Gao Z, Xie J, Wang Z, Zhang W, You G, Wang J, Li G, Gao Z, Xie J. Olfactory schwannoma: A report of two cases and literature review.Neurol India 2014;62:429-431


How to cite this URL:
Wang Z, Zhang W, You G, Wang J, Li G, Gao Z, Xie J, Wang Z, Zhang W, You G, Wang J, Li G, Gao Z, Xie J. Olfactory schwannoma: A report of two cases and literature review. Neurol India [serial online] 2014 [cited 2020 Dec 4 ];62:429-431
Available from: https://www.neurologyindia.com/text.asp?2014/62/4/429/141289


Full Text

 Introduction



Olfactory schwannoma is an exceedingly rare disease, and until date, only 46 cases have been reported worldwide. We present two cases of olfactory schwannoma in whom the preoperative diagnosis was olfactory groove meningioma.

 Case Report



Case 1

A 38-year-old woman presented with a history of intermittent vomiting of one-month duration. Examination revealed no neurological deficits except diminished sense of smell. Cranial magnetic resonance imaging (MRI) revealed a 43 mm × 38 mm solid cystic lesion in left anterior cranial fossa with mixed T1- and T2-weighted signals. The lesion enhanced significantly on contrast administration [Figure 1]a-d. Preoperative diagnosis was left olfactory groove meningioma. Intraoperatively, the lesion was gray-white in color and slightly tough with clear boundaries in the left olfactory groove invading the ethmoidal sinus. The lesion was completely excised [Figure 1]e and f Postoperative period was uneventful with little improvement in sense of smell. Histopathological diagnosis was olfactory schwannoma. Microscopic images showed Antoni A type tumor cells, round or spindle-shaped, and aligned regularly as a fibrous cord or vortex structure (single-headed arrow); and Antoni B type cells were also seen (double-headed arrow) [Figure 1]g.{Figure 1}

In another case, MRI scan showed an ovary lesion in the anterior cranial fossa [Figure 2]a-d. The preoperative impression was olfactory groove meningioma. Postoperatively, MRI scan showed that the tumor was totally removed [Figure 2]e and f. Histological examination confirmed the diagnosis of olfactory groove schwannoma [Figure 2]g.{Figure 2}

The common cranial nerves for schwannomas are eight, facial nerves, and trigeminal. Schwannoma of the olfactory bulb is uncommon as the olfactory nerve is unsheathed by schwann cells. Until date, there have been no convincing theories that are widely accepted to explain the origin of olfactory groove schwannoma. [1],[2],[3],[4] Thus far, only 46 cases of olfactory schwannomas have been reported [5] In most reported cases of olfactory groove schwannoma, the chief complaints were headache, vomiting, seizure, hyposmia, diplopia, or even anosmia. [6],[7],[8] Physical examination often revealed loss or reduced sense of smell, which is often neglected by the patient. Surgery is the preferred treatment for olfactory schwannoma. Cerebrospinal fluid rhinohroea and associated central nervous system infections are the most common complications of the surgery. Often the differential diagnosis is olfactory groove schwannoma and is often the preoperative diagnosis in most of the reported cases. [5],[9] Histological examination confirms the diagnosis.

References

1Esiri M. Russell and Rubinstein′s pathology of tumors of the nervous system. Sixth edition. J Neurol Neurosurg Psychiatry 2000;68:538D.
2Redekop G, Elisevich K, Gilbert J. Fourth ventricular schwannoma. Case report. J Neurosurg 1990;73:777-81.
3Huang PP, Zagzag D, Benjamin V. Intracranial schwannoma presenting as a subfrontal tumor: Case report. Neurosurgery 1997;40:194-7.
4Figueiredo EG, Soga Y, Amorim RL, Oliveira AM, Teixeira MJ. The puzzling olfactory groove schwannoma: A systematic review. Skull Base 2011;21:31-6.
5Sauvaget F, Francois P, Ben Ismail M, Thomas C, Velut S. Anterior fossa schwannoma mimicking an olfactory groove meningioma: Case report and literature review. Neurochirurgie 2013;59:75-80.
6Adachi K, Yoshida K, Miwa T, Ikeda E, Kawase T. Olfactory schwannoma. Acta Neurochir (Wein) 2007;149:605-10.
7Darie I, Riffaud L, Saikali S, Brassier G, Hamlat A. Olfactory ensheathing cell tumour: Case report and literature review. J Neurooncol 2010;100:285-9.
8Saberi H, Khashayar P. Olfactory groove schwannoma masquerading as an orbital mass. Neurosciences (Riyadh) 2008;13:73-6.
9Tan TC, Ho LC, Chiu HM, Leung SC. Subfrontal schwannoma masquerading as meningioma. Singapore Med J 2001;42:275-7.