[Basal encephalomeningocele in an adult--a case report and clinico-anatomical classification].

A 53-year-old male was admitted with complaints, of the recurrent cerebrospinal fluid rhinorrhea and meningitis. Basal encephalomeningocele was revealed by radionuclide cisternography, skull x-ray studies, and CT scan. Then, it was confirmed by operation. In reviewing the literature, we proposed a new classification of fronto-basal encephalomeningocele from clinical standpoints. 1) Anterior type; detectable facial anomalies, hypertelorism, building frontal mass or masses. Reparative operation is easy. 2) Intermediate type; no facial anomalies, cerebrospinal fluid rhinorrhea, meningitis, nasal polyp. Good results can be expected through intracranial approach. 3) Posterior type; associated many congenital anomalies such as coloboma, agenesis of the corpus callosum, and cleft palate and lip. In this type, intracranial operation has potential hazards. In our case, elevated CSF pressure due to hemodialysis for chronic renal failure may result in the late onset of CSF rhinorrhea. Etiology of 10 reported cases of the basal encephalomeningocele in Japan was also discussed.