Psychosis After Resection of Ganglioglioma or DNET: Evidence for an Association

Summary: Purpose: David Taylor and Murray Falconer suggested that some patients may develop a psychotic illness after resection of a ganglioglioma that led to intractable seizures. They implied that the mechanism of this association remained unclear. This concept is currently not universally accepted (M. Trimble, personal communication).
Methods: We studied six children or young adults from four centers who developed psychosis after resection of a ganglioglioma or dysembryoplastic neuroepithelioma (DNET).
Results: All patients were operated on because of intractable epilepsy. The lesions involved mainly the temporal lobe. Patients had good outcomes for seizure control. In none of the six was potentially psychogenic medication used nor were the psychotic symptoms postictal in nature. The psychosis was schizophreniform with paranoid features and prominent depressive symptoms. Although some behavioral abnormalities were described preoperatively, none had been psychotic before operation. This type of psychotic reaction was not encountered in the four centers in a comparable period after resection of other types of lesions. This complication is rare; it occurred in only one of 39 patients who had such a lesion resected.
Conclusions: Psychotic illness may rarely occur after resection of a ganglioglioma or DNET for treatment of intractable epilepsy. This does not seem to occur after removal of other types of lesions. Because the patients had good outcomes for seizures, the mechanism may be related to "forced normalization." The original observations of Taylor and Falconer are confirmed by this study; the reasons for the selective occurrence, however, remain speculative.