Open Access
CC-BY-NC-ND 4.0 · Indian Journal of Neurosurgery 2017; 06(02): 153-154
DOI: 10.1055/s-0037-1606308
Letter to the Editor
Thieme Medical and Scientific Publishers Private Ltd.

Olfactory Groove Schwannoma: A Case Report

Stylianos Pikis
1   Department of Neurosurgery, “Korgialenio-Benakio,” The Red Cross Hospital, Athens, Greece
,
Yakov Fellig
2   Departments of Neurosurgery, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
,
Emil Margolin
3   Departments of Neurosurgery, Hadassah—Hebrew University Medical Center, Jerusalem, Israel
› Author Affiliations
Further Information

Address for correspondence

Emil Margolin, MD, PhD
Department of Neurosurgery, Hadassah—Hebrew University Medical Center
P.O. Box 12000, Jerusalem 91120
Israel   

Publication History

05 March 2017

25 May 2017

Publication Date:
29 August 2017 (online)

 

We would like to report a case of a 71-year-old woman who presented to the neurosurgery clinic due to an incidentally discovered olfactory groove schwannoma. Magnetic resonance image of the brain was obtained ([Fig. 1A–C]). Due to the patient's advanced age and the benign imaging features of the lesion, monitoring was decided upon. However, growth of the lesion was noted on follow-up and gross total resection was done ([Fig. 1D]). Histopathology revealed schwannoma ([Fig. 2]). At the 1-year follow-up, the patient had right-sided anosmia.

Zoom
Fig. 1 Coronal (A), sagittal (B), and axial (C) T1-weighted, gadolinium-enhanced, brain MR image demonstrating a well-circumscribed, homogenously enhancing, extra-axial, anterior cranial fossa lesion eroding the ethmoid bone. Coronal (D) T1-weighted, gadolinium-enhanced, brain MR image showing gross total resection of the tumor.
Zoom
Fig. 2 Histopathologic examination revealed pauci-cellular and more cellular regions (A) composed of spindle cells, without marked nuclear atypia or increased mitotic activity, with ill-formed nuclear palisading (B), diffusely immune-positive for S-100 (C).

Olfactory groove schwannomas are rare, extra-axial, benign tumors. In contrast to other intracranial schwannomas, they frequently affect young males.[1] [2] Moreover, since the olfactory bulb is devoid of Schwann cells,[1] [3] their pathogenesis is unclear with several theories proposed: The developmental theories suggest mesenchymal pial cell transformation into Schwann cell or aberrant neural crest cell migration.[1] [2] [4] The nondevelopmental theory suggests origin from Schwann cells present in adjacent structures.[1] [2] [4] Finally, reactive Schwann cell formation from multipotential mesenchymal cells has also been proposed.[1]

Histopathologic findings pathognomonic for schwannoma include densely packed elongated cells with palisading nuclei (Antoni A pattern) alternating with less cellular regions (Antoni B pattern).[3] On immunohistochemistry, schwannomas stain was positive for S-100[3] and CD-57 (Leu-7)[2] [4] and negative for smooth muscle α-actin.[4] Management should be individualized, and includes observation, surgical resection, and radiosurgery.[3]

In conclusion, the pathogenesis of olfactory groove schwannomas remains unclear. They should be included in the differential diagnosis of anterior cranial fossa neoplasms.


Conflict of Interest

None.

Funding

None.



Address for correspondence

Emil Margolin, MD, PhD
Department of Neurosurgery, Hadassah—Hebrew University Medical Center
P.O. Box 12000, Jerusalem 91120
Israel   


Zoom
Fig. 1 Coronal (A), sagittal (B), and axial (C) T1-weighted, gadolinium-enhanced, brain MR image demonstrating a well-circumscribed, homogenously enhancing, extra-axial, anterior cranial fossa lesion eroding the ethmoid bone. Coronal (D) T1-weighted, gadolinium-enhanced, brain MR image showing gross total resection of the tumor.
Zoom
Fig. 2 Histopathologic examination revealed pauci-cellular and more cellular regions (A) composed of spindle cells, without marked nuclear atypia or increased mitotic activity, with ill-formed nuclear palisading (B), diffusely immune-positive for S-100 (C).