Cavernous hemangioma of the abducens nerve: clinical implication of duplicated variants: case report.

Background and Importance: A cavernous hemangioma arising from the abducens nerve has not been previously reported in the literature. Based on the surgical experience with this case, the authors discuss the clinical importance and resectability potential of a duplicated abducens nerve.
Clinical Presentation: A 54-year-old woman presented with a recurrence of diplopia that had occurred 3 years before this admission and had spontaneously resolved without any specific treatment. On admission, there were no specific neurological deficits. Magnetic resonance imaging revealed a cone-shaped mass on the right anterior cerebellopontine angle with hemorrhagic change. Surgical resection via a standard right lateral suboccipital approach was performed. A cystic mass was found emerging from the entry zone of the Dorello canal and encircling the larger branch of the duplicate abducens nerve. Because there was no demarcation between the mass and origin branch, both were removed en bloc. Pathology revealed the presence of a cavernous hemangioma mixed with nerve tissue. Despite preserving a small branch of the duplicate abducens nerve, the patient had permanent right abducens palsy.
Conclusion: A cavernous hemangioma arising from the abducens nerve should be suspected as a possible diagnosis for a cystic mass on the anterior cerebellopontine angle. Although duplication of the abducens nerve has not been clearly confirmed on clinical grounds, sacrificing the larger branch during surgery may lead to permanent abducens palsy, as in our case.