The Role of the Mammillary Bodies in Memory: A Case of Amnesia Following Bilateral Resection

Background and Objectives: Craniopharyngioma (CP) patients typically show good neuropsychiatric outcome following tumor resection. We present the case of a 51-year old woman who sustained damage to white matter pathways during surgery resulting in a disconnection of the Papez circuit (loss of bilateral mammillary bodies, columns of the fornix and mammillothalamic tracts). Methods and Results: Neuropsychological evaluations were completed at 10 and 30 weeks post-operatively, and indicated both retrograde and severe anterograde amnesia, as well as persistent depression. At the second evaluation, most cognitive deficits had improved, but memory and mood deficits remained. Metamemory and priming remained intact. Conclusions: This case illustrates a profound neuropsychiatric morbidity associated with a surgery that is typically considered benign and confirms the well-known dissociation between explicit recollection of newly learned information and less conscious forms of learning and memory. This rare pathology provides further information regarding the role of the mammillary bodies in memory. Received 10 August 2005 Accepted 3 February 2006 Despite being a histologically benign tumor, the adhesive nature and suprasellar location of craniopharyngiomas (CP), with proximity to subcortical structures and critical memory pathways, presents cognitive and psychiatric risks for patients undergoing surgical resection. As CPs predominate in the first two decades of life, the majority of research has focused on pediatric cognitive outcome. Preand post-operative executive dysfunction and greater visuospatial than verbal intellectual deficits have been reported in children (Cavazzuti et al. 1983). Most research on adult patients suggests Eur. J. Psychiat. Vol. 20, N.° 2, (88-95) 2006