Atypical Foster Kennedy Syndrome With Orbital Apex Involvement Secondary to Intracranial Meningiomatosis: A Case Report.

BACKGROUND Foster Kennedy syndrome is a rare neuro-ophthalmologic entity classically associated with anterior cranial fossa tumors, particularly meningiomas. Its slow evolution often leads to insidious, initially asymptomatic visual loss, resulting in delayed diagnosis. We describe an atypical presentation with unusual clinical features and a complex pathophysiological mechanism. CASE REPORT A 43-year-old man presented with left conjunctival chemosis as the initial clinical manifestation. His history was notable for long-standing endocrine abnormalities without prior specialized evaluation. Ophthalmologic examination additionally revealed bilateral proptosis, left complete ophthalmoplegia with ipsilateral optic atrophy, and contralateral optic disc edema. Neuroimaging demonstrated intracranial meningiomatosis; all of these findings were consistent with type 1 Foster Kennedy syndrome. The chemosis was attributed to meningioma extension into the left cavernous sinus and orbital apex, resulting in orbital apex syndrome. Contralateral papilledema reflected intracranial hypertension due to impaired dural venous outflow via superior sagittal sinus obstruction. A conservative approach was used, including corticosteroids to reduce mass effect and acetazolamide to decrease intracranial pressure, aiming to preserve optic nerve function. The clinical evolution was favorable. CONCLUSIONS This case illustrates an atypical form of Foster Kennedy syndrome with distinctive etiopathogenic and pathophysiological features. Hormonal disturbances may have contributed to meningiomatosis development and growth, while orbital apex involvement suggests a complex mechanism beyond isolated optic nerve compression. Conservative management remains appropriate first-line therapy in multifocal disease with intracranial hypertension, with the goal of preserving visual function.