Cerebrospinal Fluid Rhinorrhea and a Lytic-Appearing Lesion of the Posterior Cranial Fossa

Abstract

A man in his 60s presented to the otolaryngology clinic with a 1-month history of clear drainage from his left naris during activity. Approximately 1 month prior he had been admitted to the hospital and treated for meningitis. During his hospital course, a computed tomographic (CT) scan of his head revealed a lytic lesion of the left occipital bone. After treatment with intravenous antibiotics and steroids, his neurologic examination results returned to baseline, and he was discharged home. Magnetic resonance imaging (MRI) was deferred to the outpatient setting. At the otolaryngologist's office, the patient stated that he had not experienced otalgia, otorrhea, tinnitus, or vertigo. His examination revealed clear nasal discharge and a normal otoscopic finding. His audiogram demonstrated normal sloping to moderate sensorineural hearing loss with type A tympanometry result on the right and type A on the left. His word recognition score was 100% bilaterally. The collection of nasal discharge for β-2 transferrin analysis was attempted, but insufficient quantity was obtained. To evaluate for a skull base defect and cerebrospinal fluid (CSF) leak, a noncontrast CT scan of the temporal bones was obtained (Figure , A and B). This demonstrated a large area of bony destruction and osteolysis involving the left occipital bone. A T2-weighted MRI sequence showed a lesion, isointense to CSF, with thinning of the bony cortex (Figure, C and D). Based on the imaging, the differential diagnosis included metabolic, infectious, or metastatic lesions to the bone.