Delayed cerebrospinal fluid rhinorrhea after gamma knife surgery in a patient with a growth hormone-secreting adenoma.

We report a patient who developed delayed cerebrospinal fluid (CSF) rhinorrhea 11 years after gamma knife radiosurgery for a growth hormone (GH)-secreting adenoma. The treatment dose was 18 Gy for the tumor margin (50% isodose). One year later, an MRI of the head revealed that the tumor size had decreased. Eleven years later, the patient developed CSF rhinorrhea from the left nostril. Subsequent MRI examination revealed complete remission of the tumor in the sella turcica and the empty sella. The patient was admitted for direct endoscopic surgical repair of the skull base. We suggest that the cause of the CSF rhinorrhea is secondary empty sella. The other potential causes may be the original invasiveness of the tumor or delayed radiation damage to the mucous membranes of the skull. Long-term follow-up is required to monitor recurrence of CSF rhinorrhea.