[Endometriosis--new perspectives. 1. Pathology and physiopathology].

Endometriosis is a disease characterized by the occurrence of ectopic endometrium, most frequently in the pouch of Douglas and the ovaries. The disease is diagnosed at operation and occurs practically exclusively in women of fertile age. The symptoms are, in particular, diffuse low abdominal pain, dyspareunia, infertility and dysmenorrhoea. The prevalence of the disease is unknown but has been estimated as about 1-2%. The etiology is still unknown. The classical theories about 1) retrograde implantation of endometrium from menstruation and 2) metaplasia of the coelom epithelium are still current. A series of recent observations of increased macrophage activity, reduced cellular immunity and deviations in the complement system suggest, however, that special immunological factors also play a causal role. Endometriotic tissue has great morphological and biochemical similarities with endometrium and contains, similarly, receptors for steroid sex hormones but in lower concentrations and with an increased relationship between progesterone and oestrogen receptors. The pathophysiological basis for the infertility correlated with the disease is only partially understood. Apart from obvious anatomical causes, the occurrence of the luteinized unruptured follicle syndrome and alterations in the content of steroid hormones and prostaglandins in the peritoneal fluid are possible causes.