High recurrence rate following aspiration of colloid cysts in the third ventricle.

Sixteen patients treated between 1969 and 1989 for a colloid cyst of the foramen of Monro by stereotactically guided aspiration (not stereotactic extirpation) were evaluated to assess the long-term outcome of the procedure. Thirteen of these patients required reoperation due to an acute comatose state, failure to achieve permanent reduction of the cyst, or symptomatic hydrocephalus. Of these 13, six were treated twice and two were treated three times by stereotactic aspiration. Five patients underwent microsurgical extirpation and three had a shunt placed following a failed aspiration. Failure of the first procedure was detected within the first 2 months after treatment in eight patients and after more than 6 years in seven. Following stereotactic aspiration, three patients experienced a temporary memory deficit and confusion and one patient suffered a central pain syndrome. Eleven of the 26 procedures were followed by a recurrence 6 to 15 years after treatment; seven recurrent cysts were detected after more than 8 years. Of the patients with recurrences, three did not undergo repeat surgery but showed an increase in cyst size at the latest follow-up examination. It is suggested that radical removal by open or stereotactically guided microsurgery is the method of choice since stereotactic aspiration fails to offer a radical or permanent treatment for colloid cysts of the third ventricle.