A Case Report of Abducens Nerve Palsy Which Developed Most Likely Due to Invasive Fungal Sinusitis of Sphenoid Sinus

Abstract

Invasive fungal sinusitis of the sphenoid sinus can cause serious symptoms due to involvement of surrounding structures such as the skull base and cavernous sinus, and may be fatal. Thus, early diagnosis and appropriate treatment are crucial for this disease. We report a case of invasive fungal sinusitis of the sphenoid sinus in which abducens nerve paralysis developed. An 81-year-old man with diplopia was referred by an ophthalmologist due to MRI findings indicating possible sphenoid mycosis. The patient had no symptoms other than diplopia. A CT scan showed soft tissue density with calcification in the right sphenoid sinus and a bone defect in the posterior wall of the sphenoid sinus, which corresponded to the abducens nerve tract on the clivus. In serum, the β-D glucan level was not elevated, but aspergillus antigen was elevated. Invasive fungal sinusitis was diagnosed based on the CT and biochemical findings. The patient underwent endoscopic sinus surgery on the day of examination, followed by intravenous administration of an azole-based antifungal agent, VRCZ. The postoperative clinical course was uneventful, with complete neurological recovery of the abducens nerve and improvement of the aspergillus antigen level in serum. Measurement of the aspergillus antigen level in serum was useful in early diagnosis and for evaluation of the therapeutic effect.