ABSTRACT
Endometriosis is defined histologically as the presence of endometrial glands and stroma outside the uterine cavity. The use of the scanning microscope has altered the histological interpretation of endometriosis. Vasquez and colleagues described three different endometriotic implants. Laparoscopy does not distinguish between these three types, because only the sequelae of endometriosis are visible at laparoscopy: haemorrhage, adhesions, accumulation of fluid and inflammatory reaction. Oestrogen, progesterone and androgen receptors are all quantifiable in endometriotic tissue. Oestrogen receptors are at a lower level and do not have the pronounced cyclical changes that occur in endometrium. The endometrial fragments in menstrual effluent are composed of necrotic and living cells, which do not survive in ectopic locations because of programmed cell death. Changes have been observed in both humoral and cell-mediated immunity in women with endometriosis. Endometriosis is associated with chronic inflammation. Macrophage numbers are increased and more active in peritoneal fluid from women with endometriosis.
