A mid-adolescent boy presenting with progressive headaches, blurry vision, and left eyelid ptosis was found to have a 6 mm lobulated saccular aneurysm at the left posterior communicating artery origin, treated successfully with endovascular intervention resulting in gradual neurological recovery.
A mid-adolescent male presented with cranial nerve III palsy as the primary clinical manifestation of an unruptured intracranial aneurysm.
Non-contrast CT of the brain was normal despite the presence of a significant intracranial aneurysm.
MR angiography identified a 6 mm lobulated, saccular aneurysm of the left internal carotid artery at the origin of the posterior communicating artery.
Prompt endovascular treatment of the aneurysm resulted in gradual neurological recovery.
Pediatric intracranial aneurysms are uncommon and are often linked to congenital or developmental vascular anomalies.
Early vascular imaging is emphasized as necessary when isolated cranial nerve III palsy is identified in adolescent patients.
This research describes the case of a teenage boy who developed progressive headaches, blurry vision, and a drooping left eyelid. Doctors found that his left eye pupil was enlarged and sluggish, and he had difficulty moving his eye in certain directions — signs of a condition called cranial nerve III palsy, which affects the nerve controlling eye movement. A standard CT brain scan came back normal, but a more specialized imaging test called MR angiography revealed a small (6 mm) balloon-like bulge (aneurysm) in a blood vessel at the base of his brain, near where two important arteries branch off. He also had aneurysms involving a second artery. A minimally invasive procedure performed through the blood vessels (endovascular treatment) was used to treat the aneurysm, after which his neurological symptoms gradually improved. This case matters because brain aneurysms in children and teenagers are rare and can be easy to miss, especially when symptoms seem relatively mild or could be explained by more common, harmless conditions. The fact that a normal CT scan gave false reassurance highlights that more advanced vascular imaging may be needed when a teenager presents with a drooping eyelid and abnormal eye movements — a combination of findings that can signal a dangerous, unruptured aneurysm pressing on a nearby nerve. This research suggests that doctors should maintain a high level of suspicion for aneurysms in young patients presenting with isolated third cranial nerve palsy, and should not rely solely on standard CT scans to rule out vascular causes. Early specialized imaging and prompt treatment may prevent potentially life-threatening complications such as aneurysm rupture and brain hemorrhage.
Liaqat A, Khalid A, Ryan P. (2026). Concurrent posterior communicating and ophthalmic artery aneurysms in a teenager: diagnostic and endovascular management considerations.. BMJ case reports. https://doi.org/10.1136/bcr-2025-271968