[Primary arachnoid cyst in an adult (author's transl)]

Primary arachnoid cyst in adults seems to be relatively rare. Our case was a 42-year-old female, who complained of diplopia, dizziness, mild headache, and showed papilledema. Right carotid angiograms revealed the characteristic findings. Right fronto-parietal craniotomy was then performed. In the operation, a large, thin walled cyst was found on the surface of the right cerebral hemisphere. When the membrane was removed, essentially normal, but slightly atrophi gyri, could be seen. Aspiration of encapsulated fluid, and extirpation of the cyst wall resulted in an excellent improvement. Microscopically, the wall of the cyst was lined with normal arachnoid cells. The case was presumed to be a primary arachnoid cyst for the reasons that no definited etiological factor could be found in this case an no abnormal findings other than the cyst itself could be found in the operation and in the histological specimen. We discuss reported cases in our review, and about pathological findings, symptoms, diagnosis, and treatment of this disease.