Bilateral Optic Neuropathy Mimicking Neuromyelitis Optica in the Setting of Intracranial Germinoma

Bilateral optic neuropathy is uncommon in adults with a prevalence varying from 19% -50% of all optic neuropathies [1]. The most common etiology is Neuromyelitis Optica (NMO) or Devic’s disease. Other less frequent etiologies include myelin-oligodendrocyte-glycoprotein (MOG) antibody, syphilis, meningioma, post-vaccinal, post-infectious (chicken pox, human herpes virus 6), acute disseminated encephalomyelitis and idiopathic. Sequential optic neuropathy is seen in multiple sclerosis, but bilateral simultaneous optic neuropathy is rare [2]. When optic neuropathy involves posterior nerve segments, long segments and the optic chiasm, NMO should be suspected. If there is involvement of the hypothalamus, basal meninges, other cranial neuropathies, sarcoidosis must be considered [3]. Primary intracranial germinoma is a rare condition and should be included in the differential diagnosis, especially if there are atypical features and inadequate response to standard treatment [4].