[Delayed cerebrospinal fluid leak post-intensity-modulated radiotherapy for nasopharyngeal carcinoma: a case report].

A 60-year-old man, who diagnosed nasopharyngeal carcinoma staged as T1N1M0 in 2003 and received 68 Gy 30 times intensity modulated radiotherapy for primary tumor, was diagnosed as "cerebrospinal fluid rhinorrhea（left side）; purulent meningitis; nasopharyngeal carcinoma（post-radiotherapy） " in 2017. The patient received an emergency repair of the cerebrospinal fluid leakage by nasal endoscope approach surgery. No rhinorrhea complained in the following 2 years. But two years later, the patient complained a recurrent rhinorrhea by no incentives. The CT scan found ethmoid-like defect change in bottom of the right sphenoid sinus bone this time and no tumor recurrence was observed in CT scan or MRI exam. Then the patient received a second time right-side endoscopic transphenoid approach cerebrospinal fluid leakage repair operation. The patient recovered well after operation and regular endoscope follow-up showed no evidence of cerebrospinal fluid rhinorrhea. This case showed that the risk of cerebrospinal fluid leakage should be considered by the use of intensity modulated radiotherapy. For the cerebrospinal fluid rhinorrhea caused by osteonecrosis after radiotherapy, emergency surgical treatment is required since conservative treatment may not be effective.