Isolated Cranial Nerve VI Palsy Due to Sellar Chordoma

Intracranial chordomas are a rare, locally aggressive tumor that infrequently involve the sellar region to mimic a pituitary adenoma. This is a case of an isolated left cranial nerve VI palsy due to an atypical appearing sellar mass with rapid progression to bilateral cranial nerve VI palsies and complete right cranial nerve III palsy. Initial tentative diagnosis of pituitary adenoma was questioned due to the rate of progression and atypical features on neuroimaging.

Poster 199 Isolated Cranial Nerve VI Palsy due to Sellar Chordoma Kelly Seidler 1, Andrew Carey 2 1 Wilmer Eye Institute, 2 Wilmer Eye Institute, Johns Hopkins University School of Medicine Introduction: Intracranial chordomas are a rare, locally aggressive tumor that infrequently involve the sellar region to mimic a pituitary adenoma. This is a case of an isolated left cranial nerve VI palsy due to an atypical appearing sellar mass with rapid progression to bilateral cranial nerve VI palsies and complete right cranial nerve III palsy. Initial tentative diagnosis of pituitary adenoma was questioned due to the rate of progression and atypical features on neuroimaging. Description of Cases: A 50-year-old white male presented with acute onset diplopia 2 days after receiving his Johnson & Johnson COVID19 booster. He had history of diabetes mellitus, hypertension and hyperlipidemia, all well-managed with oral medications. Neuro-ophthalmic examination was remarkable for an isolated left cranial nerve VI palsy. MRI brain and orbits was ordered but repeatedly delayed due to severe claustrophobia. Ophthalmologic follow-up one month later revealed slight worsening of the isolated left cranial nerve VI palsy. He was lost to follow-up for 2 months until he developed headaches, right ptosis and right ophthalmoplegia and finally completed the neuroimaging. MRI revealed a large, heterogeneously enhancing sellar and suprasellar mass with involvement of the bilateral cavernous sinuses, left petrous bone and extension into the sphenoid sinuses. The tentative diagnosis based on imaging was pituitary adenoma, however given his rapid progression and indication of bony invasion, biopsy was urgently performed. Pathology was consistent with a chordoma. Conclusions, including unique features of the case: Pituitary adenomas are the most common sellar mass. In this case, imaging findings were initially considered most compatible with an invasive pituitary adenoma by multiple radiologists and other sub-specialists. Rapid progression prompted biopsy which was indicative of a chordoma with a moderate to high Ki-67 proliferation rate. Recognition of the rapid progression and other atypical features was critical to establishing a more definitive diagnosis to guide more urgent neurosurgical intervention. References: None provided. Keywords: Ocular motility, Skull base, Tumors Financial Disclosures: The authors had no disclosures. Grant Support: None. Contact Information: Kelly Seidler, [e-mail] 2023 Annual Meeting Syllabus | 263