Extradural neurenteric cyst of the cerebellopontine angle. Case report.

Neurenteric cyst is a developmental malformation found mainly in the spinal canal. The authors report on a 47-year-old man with a neurenteric cyst of the cerebellopontine angle (CPA) who presented with progressive hearing disturbance and facial palsy. The tumor was located extradurally with marked destruction of the petrous bone around the internal auditory canal and demonstrated irregular and heterogeneous high-intensity signals on T1- and T2-weighted on MR images, which is atypical for neurenteric cysts. The pathological findings in samples obtained after resection disclosed a single epithelial layer (a feature of neurenteric cyst), which was accompanied by marked xanthogranulomatous changes. Although several neurenteric cysts have been reported in the CPA, extradural lesions with unusual imaging features and marked bone destruction have not been reported previously. This benign developmental lesion should be considered, although it is extremely rare, in patients harboring an extradural temporal bone tumor around the CPA.