Abstract 050: From Radiculopathy to Aneurysm: Pupil‐Sparing ICA‐PCOM Discovered on Cervical MRI and Coiled

Introduction Unruptured intracranial aneurysms occur in ∼2%‐3% of the general population and may be more prevalent in older adults, women, and those with relevant familial/genetic backgrounds. Internal carotid‐posterior communicating artery (ICA‐PCOM) aneurysms are a classic cause of oculomotor nerve compression. While many present with subarachnoid hemorrhage, they can also present with non‐traumatic subdural hematoma or isolated oculomotor palsy. Preoperative asymptomatic cases are uncommon; “splitting” of the oculomotor nerve by an aneurysm has been described intraoperatively as a mechanism of neuropathy. Purpose To present a case of an asymptomatic, pupil‐sparing large ICA‐PCOM aneurysm incidentally detected on cervical spine MRI. Materials and Methods The patient was identified in routine clinical practice. Results A 60‐year‐old woman with diabetes, asthma, hyperlipidemia, systemic lupus erythematosus, migraine, and anxiety presented with unsteadiness, memory concerns, and right‐sided neck pain radiating to the arm with intermittent numbness and subjective weakness. Neurologic exam showed decreased light touch over the right shoulder region, brisk deep tendon reflexes (3+) in both upper and lower limbs, and bilateral positive Hoffmann signs. Pupils were equal and reactive with no ptosis, diplopia, or other oculomotor deficit (pupil‐sparing). Cervical spine MRI obtained for radiculopathy revealed an ovoid T2 hypointensity in the left suprasellar cistern suspicious for a large internal carotid artery aneurysm (∼15 mm). The study also showed a C3‐4 broad‐based disc‐osteophyte complex, left‐predominant, mildly deforming the ventral cord. Diagnostic cerebral angiography confirmed a large, bi‐lobulated, wide‐neck left ICA‐PCOM aneurysm measuring 15.4 × 13.6 × 13.5 mm. The aneurysm was treated with endovascular coil embolization; the immediate post‐procedure course was uncomplicated, and the patient remained without oculomotor deficits. Conclusion Asymptomatic, incidentally discovered ICA‐PCOM aneurysms can occur despite absent pupillary involvement. Vigilant review of suprasellar structures on non‐targeted studies such as cervical MRI can uncover actionable pathology. Endovascular coiling is a feasible treatment option for large, wide‐neck ICA‐PCOM aneurysms identified in this context. image