Sequential Bilateral Facial Nerve Palsy With Right Abducens Nerve Palsy in Possible Neurosarcoidosis

Neurosarcoidosis is an uncommon manifestation of sarcoidosis that can present with cranial neuropathies.Facial nerve involvement is well recognized, but the sequential development of bilateral facial nerve palsy with right abducens nerve palsy, together with a focal cavernous sinus-orbital apex lesion, presents a diagnostic and localizing challenge.We report a case of possible neurosarcoidosis with this clinicoradiological presentation.A 40-year-old man presented with right abducens nerve palsy and right lower motor neuron facial weakness.The following day, left facial weakness was also evident, resulting in sequential bilateral facial nerve palsy.Ophthalmological examination demonstrated bilateral grade I papilledema.Contrast-enhanced MRI showed asymmetric soft-tissue thickening and enhancement of the right cavernous sinus extending to the right orbital apex.Systemic evaluation revealed prominent bilateral hilar and mediastinal lymphadenopathy, including a 3.4-cm subcarinal lymph node, and an elevated serum angiotensin-converting enzyme level.CSF and available infectious investigations did not identify an alternative infectious etiology.A clinical diagnosis of possible neurosarcoidosis was made.Tissue confirmation was recommended but was not obtained.The patient received IV methylprednisolone followed by oral corticosteroids and weekly methotrexate, with subsequent clinical improvement.This case highlights the importance of correlating the distribution of cranial nerve involvement with neuroimaging findings.When neurological examination demonstrates cranial nerve involvement extending beyond the apparent territory of a focal lesion, consideration of a broader inflammatory or granulomatous process and appropriate systemic evaluation may be warranted.