confirmed. The patient's vision loss and eye movements improved after the operation (Fig. 1C). In the examination, the light reflex was completely natural.
DISCUSSIONOnodi cell, which is a type of ethmoid cells, is seen in routine radiological imaging at 8% to 14% and in cadaver studies up to 60%. 8,9 Its close proximity to the orbital apex increases the clinical importance of the lesions of this area. Onodi cell mucocele has been shown extremely rarely in the literature. Mucocele actually arises with decreased sinus drainage. It is a slow growing, mucus containing cystic lesion in benign nature. Clinically, it is generally asymptomatic but it may present with various compression findings depending on the location. 6,10 Direct mass compression effect was shown primarily in the pathogenesis of optic neuropathy for onodi cell mucocele. Apart from this, superinfection and ischemia, which develop as a result of compression of the vasa nervorum, are among other causes. Response to treatment is good even in patients without infection and inflammation.Radiological imaging methods play an important role in the diagnosis of mucocele, since the lesion has no specific clinical and laboratory findings. This importance increases even more in patients presenting with compression symptoms. With imaging, the diagnosis of mucocele is easily made and it is a guide for the necessary surgical procedure. The onodi cell mucocele shows the cystic enlargement structure typically found in the upper lateral of the sphenoid sinus. It can be monitored at different intensity and density due to the amount of protein in the mucus content and secondary infections. Although post-contrast imaging shows peripheral minimal enhancement, it is not usually contrasted. While CT is good at showing the expansion in the bony structure, MR clearly reveals the relationship with neighboring structures. The treatment is surgical resection with an endoscopic approach. 7,11 In conclusion, as we have shown in our case, onodi cell mucocele is a rare cause of sudden vision loss. Imaging methods are essential for early diagnosis and promptly treatment, so patients' symptoms can be reversible.