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

Lee SK, Moon KS, Lee KH, Jung S - J Korean Neurosurg Soc (2013)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Korea.

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.

No MeSH data available.


Related in: MedlinePlus

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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Figure 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.

Mentions: A 76-year-old male patient, without significant medical illnesses, presented with right facial numbness and hearing impairment for a month. The patient showed no neurological symptoms or signs except hypoestheia/hypoalgesia of the trigeminal nerve and mild hearing impairment on the right side. Magnetic resonance imaging revealed a multi-septated cystic mass on the right cerebellopontine angle (Fig. 1A, B). The epidermoid cyst was excluded as a possible preoperative diagnosis based on diffusion-weighted image (Fig. 1C). There was no enlargement of the internal auditory canal on computed tomography scans with bone window (Fig. 1D). Pure tone audiometry and speech discrimination score showed almost normal hearing status. There were no limitations observed with the extraocculomotor movement (EOM). The preoperative diagnosis was a trigeminal schwannoma which was mainly cystic nature. Surgical resection was performed with the standard right lateral suboccipital approach. A thin-walled cystic mass displaced the lower CNs inferolaterally, the vestibulo-facial CN complex laterally, and the trigeminal nerve superiorly. After being fenestrated through its cyst wall, the mass was found to be originating from the abducens nerve. The abducens nerve seemed normal in contour and diameter, although it compressed other surrounding CNs. The tumor and its origin CN were medially located anterior to the pontine membrane and coursed within the cerebellopontine cistern (Fig. 2). Following a meticulous dissection, the cystic tumor was totally removed without any injury of the origin CN. Pathological examination revealed a schwannoma (Fig. 3). Postoperatively, the patient complained of transient diplopia without definitive EOM limitation. His symptom disappeared by 3 months after operation.


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

Lee SK, Moon KS, Lee KH, Jung S - J Korean Neurosurg Soc (2013)

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.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3756133&req=5

Figure 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.
Mentions: A 76-year-old male patient, without significant medical illnesses, presented with right facial numbness and hearing impairment for a month. The patient showed no neurological symptoms or signs except hypoestheia/hypoalgesia of the trigeminal nerve and mild hearing impairment on the right side. Magnetic resonance imaging revealed a multi-septated cystic mass on the right cerebellopontine angle (Fig. 1A, B). The epidermoid cyst was excluded as a possible preoperative diagnosis based on diffusion-weighted image (Fig. 1C). There was no enlargement of the internal auditory canal on computed tomography scans with bone window (Fig. 1D). Pure tone audiometry and speech discrimination score showed almost normal hearing status. There were no limitations observed with the extraocculomotor movement (EOM). The preoperative diagnosis was a trigeminal schwannoma which was mainly cystic nature. Surgical resection was performed with the standard right lateral suboccipital approach. A thin-walled cystic mass displaced the lower CNs inferolaterally, the vestibulo-facial CN complex laterally, and the trigeminal nerve superiorly. After being fenestrated through its cyst wall, the mass was found to be originating from the abducens nerve. The abducens nerve seemed normal in contour and diameter, although it compressed other surrounding CNs. The tumor and its origin CN were medially located anterior to the pontine membrane and coursed within the cerebellopontine cistern (Fig. 2). Following a meticulous dissection, the cystic tumor was totally removed without any injury of the origin CN. Pathological examination revealed a schwannoma (Fig. 3). Postoperatively, the patient complained of transient diplopia without definitive EOM limitation. His symptom disappeared by 3 months after operation.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosurgery, Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, Korea.

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.

No MeSH data available.


Related in: MedlinePlus