MRI Negative Meningioma Causing Isolated Abducens Nerve Palsy

A 51-year-old female with history of prediabetes, hypertension, obesity and MVC with mild traumatic brain injury presented for evaluation of a partial left abducens palsy. She reported transient and progressive diplopia over the years following her traumatic brain injury. She had also been treated for a sinus infection during an episode of subjective worsening of diplopia. Ophthalmologic evaluation was unremarkable for any ophthalmoplegia until six months prior to her clinic visit with Neurosurgery. She underwent an extensive rheumatologic work-up that was unremarkable. After serial ophthalmologic evaluation she was treated with prism glasses which she required more frequently as time went on. Upon presentation to our clinic she also endorsed intermittent left retro-orbital and facial pain. Review of CT imaging demonstrated a sclerotic lesion near Dorello canal that was present upon initial CT imaging for her trauma ten years prior. On neurologic examination her cranial nerves were intact except for an isolated left eye lateral gaze palsy with intact conjugate right eye medial gaze. MRI redemonstrated the sclerotic lesion without any evidence of any other underlying lesion. Patient was offered surgical decompression with the counsel that her palsy could worsen. She underwent a lumbar puncture with elevated opening pressure of 27 cm H2O and a lumbar drain was placed. SSEPS and cranial nerve 5–8 were monitored. She then underwent a middle fossa approach to the petrous apex for decompression with the assistance of ENT. During the microsurgical dissection abnormal tissue was identified and sent for pathology, which demonstrated a WHO Grade 1 meningioma. Intraoperatively the abducens nerve was identified and decompressed. We also encountered a cerebrospinal fluid leak for which the skull base was reconstructed in multiple layers. Additionally, the lumbar drain was left in place for three days postoperatively. Postoperatively the patients abducens nerve palsy worsened. Abducens palsy can be attributed to many pathologies that are non-surgical. Imaging demonstrated a bony lesion that we believed could be contributing to her deficit. She was counseled about the risks, benefits and alternatives. Ultimately, she agreed to surgical intervention, which identified a benign lesion that was not identified on imaging. The findings were surprising and highlight the need for further consideration of causality in a patient with an imaging identified lesion. In this case, however, imaging was not definitive for a tumor, which in retrospect was the most likely etiology of her abducens palsy.

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Artikel online veröffentlicht:
05. Februar 2024