Gangliocytoma of third ventricle: hyperphagia, somnolence, and dementia.

A 55-year-old man had hydrocephalus caused by a third-ventricular tumor. Mentation improved after ventricular shunting and radiation therapy. Progressive hyperphagia, obesity, memory impairment, and hypersomnolence developed 13 months later, and he died 2 years after diagnosis. At necropsy, a gangliocytoma filled the third ventricle, resulting in compression and necrosis of the ventromedial and posterior hypothalamic nuclei. Clinical manifestations were attributed to these lesions.