Porencephalic Cyst

OBJECTIVE: To discuss the first reported case of spontaneous cerebrospinal fluid (CSF) otorrhea caused by a massive CSF-containing porencephalic cyst. STUDY DESIGN: A case report and review of the literature (MEDLINE 1962-2005). SETTING: A tertiary neurotologic referral center. PATIENT: A 65-year-old woman with congenital hemiplegia presented with left-sided spontaneous CSF otorrhea of 4-month duration. An audiogram revealed a mixed hearing loss. High-resolution computed tomography revealed a thinning of the tegmen and epitympanum without an obvious defect. Magnetic resonance imaging revealed a massive porencephalic cyst essentially replacing the entire left cerebral hemisphere. INTERVENTION: A transmastoid approach with three-layered closure was used to successfully repair the sieve-like defects that were discovered in her tegmen. RESULTS: The patient remains free of drainage, and the conductive hearing loss has resolved. CONCLUSION: Spontaneous CSF otorrhea caused by a porencephalic cyst is an uncommon cause of conductive hearing loss that has never been reported before. Only a few cases of traumatic CSF otorrhea/rhinorrhea associated with a porencephalic cyst have been reported. A high level of suspicion, a beta2-transferrin assay, and appropriate radiographic imaging are required for diagnosis in adults without a history of trauma, meningitis, chronic ear disease, or previous ear surgery.