Cerebrospinal Fluid Otorrhea Caused by Arachnoid Granulation
A 45 year-old female patient was referred to our department with right ear fullness which was precipitated by changes in position. Her symptom was initiated about 3 months ago. She has been well controlled hypertension. In physical examination, air fluid level was found in her right tympanic membrane, and the level increased when she hung her head down. Pure tone audiometry examination showed the right conductive hearing loss. Impedance test showed that the right was C type and the left was A type. In order to distinguish CSF otorrhea, her middle ear fluid was aspirated, and its glucose level noted 88 mg/dL. Computed tomogram (CT) of temporal bone demonstrated a bony defect adjacent to the soft tissue lesion of posterior wall of the temporal bone with an effusion showing high attenuation in the right mastoid cavity (). Thus, we presumed that CSF otorrhea might be caused by arachnoid granulation. She underwent mastoidectomy under general anesthesia. During a procedure for canal wall-up mastoidectomy, in accordance with the findings of the CT scan, the tissue which was suspected to be arachnoid granulation was observed with the bony defect of the posterior wall. The surrounding bone was removed by a diamond drill. The granulation tissue was placed at the defect of meninx (). The tissue was obtained for a biopsy. The remained granulation tissue was shrunk by bipolar cauterization. The bony defect was reconstructed by the auricular cartilage and perichondrium complex graft. Subsequently, fibrin glue was placed over the graft. The biopsy demonstrated a fibrillary tissue (). Moreover, glial fibrillary acidic protein stain indicated a positive reaction, and we confirmed arachnoid granulation which contained a portion of parenchyma of the cerebrum (). The patient has not had any symptoms of the disorder. In addition, 1 year and 3 months after the surgery, she's been continuing follow up in the outpatient clinics without any complications or recurrence.