Post-radiation CSF Leak of Skull Base

Abstract

Objectives:

(1) Describe the presence of a skull base cerebrospinal fluid (CSF) leak that occurred in a patient after receiving radiation therapy for a residual pituitary adenoma. (2) Analyze possible factors contributing to this rare occurrence.

Methods:

Case report with a retrospective chart review.

Results:

A 49-year-old African American female received 23.4 Gy in 13 fractions of definitive external beam radiotherapy for a residual nonfunctioning pituitary adenoma involving the left parasellar area for 16 days prior to developing a CSF leak. Cisternogram demonstrated a small focus of dehiscence in the right tuberculum sella, measuring 1.5 mm in diameter with a small amount of contrast present anterior to this dehiscence. This also demonstrated fluid in the right lateral aspect of the sphenoid sinus in communication with the intracranial CSF. CSF leak may occur after radiation as a tumor shrinks and leaves defects in the skull base and dura at the tumor site. Interestingly, the CSF leak in this patient occurred at a different location than that of the pituitary tumor. This suggests that radiation may weaken the skull base at sites other than tumor sites.

Conclusions:

CSF leak is known to occur after skull base surgery, but has not previously been reported after radiation in regions of the skull base away from previous sites of surgical manipulation. This case report identifies a middle skull base CSF leak in a post-radiation patient.