An unusual site of a CSF leak following resection of a retrosigmoid acoustic neuroma.

Cerebrospinal fluid (CSF) leaks may occur after acoustic neuroma resection. These leaks are usually the result of an iatrogenic injury during removal. The retrosigmoid approach is commonly associated with leaks that occur through the lateral end of the internal auditory canal, through the perilabyrinthine cells extending to the region of the internal auditory canal, or through the retrosigmoid air cells. We describe a case of an infracochlear CSF leak that developed following the retrosigmoid resection of an acoustic neuroma. To the best of our knowledge, this leak was unique for both its location and etiology.