# A schwannoma of the olfactory nerve: a case report of a diagnostic challenge and review of the literature

## TL;DR

A rare case of a schwannoma mistaken for a meningioma highlights the importance of histopathology for accurate diagnosis.

## Contribution

This case report emphasizes the diagnostic challenges of olfactory groove schwannomas and the necessity of histopathological confirmation.

## Key findings

- A schwannoma was misidentified as a meningioma on imaging but confirmed via histopathology.
- Immunohistochemistry showed S100 positivity and Epithelial Membrane Antigen negativity, supporting schwannoma diagnosis.
- The case highlights the limitations of radiological diagnosis for skull base lesions.

## Abstract

Olfactory groove schwannomas are exceptionally rare intracranial tumors that present a significant diagnostic challenge, as they are frequently misidentified as meningiomas on preoperative imaging. We report the case of a 44-year-old woman who presented with a two-month history of headache and blurred vision. Neuroimaging revealed a large, dural-based, homogeneously enhancing extra-axial mass in the left frontal region, strongly suggestive of a meningioma. The patient underwent surgical excision of the lesion. Histopathological examination, however, revealed the classic features of a benign schwannoma, including Antoni A and B areas, nuclear palisading, and Verocay bodies. This diagnosis was confirmed by an immunohistochemical profile that was positive for S100 and negative for Epithelial Membrane Antigen. This case underscores the limitations of radiological diagnosis for skull base lesions and highlights the critical role of histopathological and immunohistochemical analysis in achieving a definitive diagnosis, which is paramount for guiding appropriate management.