J Korean Neurosurg Soc.  2013 Jun;53(6):374-376. 10.3340/jkns.2013.53.6.374.

Cystic Abducens Schwannoma without Abducens Paresis : Possible Role of Cisternal Structures in Clinical Manifestation

• Lee SK
• Moon KS
• Lee KH
• Jung S

• KMID: 2190828
• DOI: http://doi.org/10.3340/jkns.2013.53.6.374

Abstract

The abducens nerve paresis generally can aid in the presumptive diagnosis of abducens schwannoma along with the typical radiological features of schwannomas. The authors present a case of a 76-year-old male patient with a abducens schwannoma without abducens nerve paresis. Peroperatively, abducens nerve located in the cerebellopontine cistern had normal in contour and diameter, despite the mass originated from this nerve. We hypothesize that anatomic location of abducens nerve may affect the vector of tumor growth to prevent destruction of its origin, the abducens nerve.

Keyword

Abducens nerve; Anatomical location; Atypical symptom; Cistern; Schwannoma

MeSH Terms

Abducens Nerve
Humans
Male
Neurilemmoma
Paresis

Figure

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  Fig. 1 A and B : Preoperative axial T2-weighted and Gd-enahnced MRI demonstrating a large sized cystic mass on the right cerebellopontine angle with peripheral rim enhancement and internal multi-septations. C : Diffusion-weighted image showing no diffusion restriction in the cystic fluid. D : Preoperative CT scan with bone window change revealing no enlargement of internal auditory canal.

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  Fig. 2 A : Peroperative photograph before fenestration of cyst wall showing thin walled cyst mass laterally displacing the vestibulo-facial nerve complex. B : Peroperative photograph revealing anatomical relationships among the anterior pontine membrane, the mass, and origin abducens nerve. Note that the anterior pontine membrane medially located from the mass and its origin nerve and enveloped them. It became a demarcation landmark between the prepontine cistern and cerebellopontine cistern. C : Peroperative photograph after resection of the mass showing the origin abducens nerve with normal contour and diameter, and upward-displaced trigerminal nerve with partly concaved against the previous mass. T : tumor, VI : abducens nerve, V : trigeminal nerve, BS : brainstem, APM : anterior pontine membrane, VII-VIII : vestibulo-facial nerve complex.

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  Fig. 3 A : Histopathological photograph revealing the compact elongated spindle cells in Antony A area (hematoxylin-eosin; original magnification, ×100). B : Histopathological photograph demonstrating strong immunoreactivity for S-100 (original magnification, ×100).

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