Delayed Presentation of Onodi Cell Mucocele with Optic Neuropathy: A Rare Case and Literature Review

A mucocele of a paranasal sinus is a mucus filled cystic mass lined by epithelium filling the involved sinus whose ostium is obstructed. While frontoethmoidal mucoceles are common, Onodi cell mucoceles are less frequently seen. Due to its anatomic proximity to optic nerve, it can lead to devastating visual complications. A 29 year old female presented with progressive loss of vision in right eye since 20 days leading to complete loss of vision since 12 days without any nasal complaints. Endoscopy showed fullness in right spheno-ethmoidal region. Computed Tomography scan revealed a mucocoele of the right Onodi air cell causing compression of intracanalicular part of right optic nerve. Despite urgent surgical decompression of mucocele, vision could not be restored. Poor visual acuity at presentation may be associated with bad prognosis. Hence, a high index of suspicion followed by appropriate imaging (CT scan and/or MRI nose and paranasal sinus) is crucial for early diagnosis in case of unexplained progressive diminution of vision, even in setting of no nasal complaints.