J Korean Soc Radiol.  2015 Dec;73(6):413-417. 10.3348/jksr.2015.73.6.413.

Ancient Schwannoma at the Olfactory Groove Mimicking Meningioma: A Case Report

• Heo YJ
• Jeong HW

• KMID: 2130949
• DOI: http://doi.org/10.3348/jksr.2015.73.6.413

Abstract

Schwannomas are benign slow-growing nerve sheath tumors, which can develop in any peripheral or central nerve that contains Schwann cells. Schwannomas located near the olfactory groove are extremely rare and radiological diagnosis can be difficult. Moreover, ancient schwannoma is an uncommon variant, and radiologic findings are rarely reported. Herein, we reported a surgically confirmed case of ancient schwannoma at the olfactory groove in a 44-year-old woman presenting with headache and visual disturbance. Brain magnetic resonance imaging (MRI) showed a solid and cystic extra-axial mass located in the subfrontal area mimicking an olfactory groove meningioma. Histopathologic diagnosis of ancient schwannoma was confirmed by immunohistochemical staining for S100, CD56, vimentin, and other markers. Furthermore, we described the clinical manifestations, MRI characteristics, and histopathologic findings of the case, and presented a review of related literature.

MeSH Terms

Adult
Brain
Diagnosis
Female
Headache
Humans
Magnetic Resonance Imaging
Meningioma*
Nerve Sheath Neoplasms
Neurilemmoma*
Schwann Cells
Vimentin
Vimentin

Figure

• 

  Fig. 1 A 44-year-old woman with headache and visual disturbance. A, B. Contrast-enhanced T1-weighted axial (A) and sagittal (B) magnetic resonance (MR) images, showing a heterogeneously enhanced extra-axial mass with cystic areas in the left subfrontal area. Solid enhancement (arrow) in the anterior portion and a non-enhanced cystic area (arrowhead) in the posterior portion are noted. The lesion shows a clear margin with the surrounding tissue. C. T2-weighted axial MR image showing a solid mass (arrow) surrounded by high signal intensity, implying a cystic component (arrowhead). D. Diffusion MR image showing no definite diffusion restriction in the solid portion. E. Perfusion MR image showing increased relative cerebral blood volume in the solid portion (arrow) and no definite change in the cystic portion.

• 

  Fig. 2 Histologic examination, showing relatively compact areas of spindle cells (Antoni A pattern) (A), Verocay bodies are formed by palisade Schwann cells (arrows) (magnification × 40) (B). Extensive vascular hyalinization (arrowheads), one of the degenerative changes of ancient schwannoma is seen (magnification × 10). Diffuse staining for CD56 (C) and S100 (D) in cell nuclei and cytoplasm, which is typically more prominent in hypercellular areas (Antoni A) than in hypocellular areas (Antoni B), is noted (magnification × 40).

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