To report a case of nasal-type NK/T cell lymphoma occurring in the sphenoid and ethmoid sinuses of an orbital apex syndrome patient.

A 61-year-old male patient visited our hospital for the impairment of vision in the right eye for the previous month, and for right-side blepharoptosis, pain around the eyeball, and limitation of extraocular movement in the right eye for three days earlier. In MRI (magnetic resonance image) and CT (computed tomography), shades with vague boundaries were observed in the right sphenoid and ethmoid sinuses, and open biopsy and decompression were performed for the lesions. After the surgery, the vision of the right eye increased, and improvement was observed in the right blepharoptosis, the pain around the eyeball, and in the limitation of motility of the extraocular muscle in the right eye. The patient was diagnosed with nasal type NK/T cell lymphoma in biopsy, and radiotherapy and chemotherapy were performed.