**2. Patient Presentation, Diagnosis and Current Treatments**

There are various symptom patterns and different patient cohorts due to the different kinds of lesions, organs affected, size and diversity of the patient population [14–16]. Additionally, non-specific complaints may lead to consultations of various medical disciplines, delaying the diagnosis. An, on average, 10-year-long delay after the onset of symptoms in diagnosis is common [14,15]. After all, more than 60% of those diagnosed with EM report that their complaints started before the age of 20. Furthermore, there is a clear correlation between the duration, the intensity of the complaints, and the extent of the EM manifestations [14,17].

EM remains a clinically suggested diagnosis and is only definitively diagnosed after surgical exploration yields pathologically confirmed EM. Pathologic examination will demonstrate ectopic endometrial-like tissue outside of the uterus containing endometrial epithelium, glands, or stroma, or hemosiderin-laden macrophages (Mϕ) [18]. Imaging techniques such as transvaginal sonography and magnetic resonance imaging may be utilized to aid diagnosis but the methodical limitations should be taken into consideration [19,20]. So far, there are no validated biomarkers for diagnosis or therapy monitoring [21].

After diagnosis, EM patients have three classes of treatments available to them: (i) analgesics to manage symptoms, (ii) hormonal therapies designed to inhibit estrogendependent growth of lesions, or (iii) surgical ablation/excision of lesions [14]. Beyond medical treatment, many women also find symptom relief during pregnancy/breastfeeding or after menopause [22].
