[Involvement of arterial vessels in the blood supply to adenomas of the human pituitary, functional implications].

Among 190 human pituitary adenomas investigated, 140 contained arterial blood vessels (nearly 75 percent). In 160 adenomas (PRL-, GH-secreting or nonfunctioning tumors) arterial vessels were present in 80 to 90 percent of the cases, whereas in 30 corticotropic adenomas (Cushing's disease), 5 only contained arterial vessels. According to data of the literature and to our own findings, such vessels should originate from the anterior pituitary itself or from the surrounding structures (trabecular, interlobar, capsular arteries). This arterial blood supply could appear even at the microadenoma stage and increase as the tumor growths. Consequently, the blood from portal origin will be diluted or excluded, so that tumor cells would escape from hypothalamic control.