Immunocytochemical Investigations on the Vascularization of Pituitary Adenomas.

Blood vessels within pituitary adenomas were visualized using the immunocytochemical reaction for Factor VIII (von Willebrand Factor), a specific marker of the vascular endothelium. The number of immunopositive vascular profiles were counted and expressed as a mean number per one microscopic field. The results were related to the type of adenoma, established on the basis of immunocytochemical investigation using the antibodies against pituitary hormones or a-subunit (a-SU). It was found that the richest vascularization occurred in adenomas expressing follicle-stimulating hormone (FSH). The possible role of FSH in pituitary angiogenesis is discussed.