Growing evidence that endometriosis is a systemic disease.

The pathophysiology of endometriosis remains unclear. Retrograde menstruation could be a phenomenon that initiates the process, but it may not explain the entire pathophysiology of endometriosis. Current evidence suggests that endometriosis is a type of chronic inflammatory disease. Many conditions that affect the vascular endothelium, including atherosclerosis, cardiovascular disease and pre-eclampsia, have been shown to be associated with endometriosis. Evidence to date suggests a complex interaction in endometriosis between angiogenesis, hormones and immunological changes stemming from chronic inflammation, with the inflammatory cells releasing cytokines and chemokines including tumour necrosis factor-α (TNF-α). Indeed, TNF-α is considered to be one of the possible markers of endometriosis in the blood, endometrium or menstrual blood. We emphasize the importance of pursuing research for novel and safer anti-inflammatory and immunomodulatory drugs that can be used by patients with endometriosis on a long-term basis.