Neuronal hypertrophy of the subventricular part of the infundibular nucleus in hypophyseotrophic tumors (author's transl)

Abstract

For the first time, the hypertrophy of nerve cells of the basal and basolateral regions of the infundibular nucleus is reported in four male patients who suffered from pituitary neoplasms (two chromophobe adenomas, two intrasellar craniopharyngiomas). In each patient, the pituitary gland was completely destroyed. This resulted in marked degeneration of the testicles. Each patient showed remarkably large neurons in an area first described as the subventricular nucleus by Sheehan and Kovacs (1966) which we designate as the subventricular part of the infundibular (=arcuate) nucleus. Using an automatic image analyzer (Quatimet 720), the neuronal hypertrophy could be quantitatively confirmed and statistically secured when compared to normal controls. The hypertrophic neurons are marked by a variegated morphology, cytoplasmic vacuoles and a numerical increase of peripherally located Nissl bodies. Especially remarkable is the high frequency of so-called “nuclear spheroids”, that are regarded as cytoplasmic invaginations into the nucleus. Based on quantitative analytical findings and the distribution of the nuclear spheroids, the subventricular part represents a semilumar band of cells in the basal and basolateral region of the arcuate nucleus and is, as a special neuronal group, associated with certain functional states. In each case, a lack of gonadotropins and, thereby, of gonadal steroids is to be surmised. Since the arcuate nucleus represents the major part of the hypophyseotrophic region, this neuronal hypertrophy appears to indicate increased neuroendocrine activity based on a deficient negative feed-back. The subventricular part of the infundibular nucleus is an example of cerebral architectonics, discovered by pathological findings.