On the clinico-pathological significance of multinucleated giant neurons in the hypothalamic arcuate nucleus.

Several multinucleated giant neurons were demonstrated in the arcuate nucleus of hypothalamus in 5 of 35 autopsied patients. In the 2 male patients, these cells showed intranuclear cytoplasmic inclusions characteristic of a persistent humoro-neural feedback effect in gonadal atrophy. Presumably, they had no pathologic effect on the neuroendocrine function of the arcuate nucleus. In the remaining 3 patients, markedly obese females, multinucleated giant neurons showed dysgenetic, dysplastic features but no evidence of feedback effect. Since severe adiposity associated with giant neurons were present in only these 3 patients, the question of a special form of hypothalamic obesity arises. Likewise, neuronal hypertrophy of the pars subventricularis of the arcuate nucleus, as demonstrated in anorexia nervosa [Hart 1971], suggests a possible participation of this nucleus in the regulation of nutrition and of body weight. Until now, it has been attributed to the ventromedial nucleus and to the lateral portions of the hypothalamus. This appears to support the proposed interpretation in our cases.