The Application of Probe-based Confocal Laser Endomicroscopy in the Diagnosis of Deep Endometriosis

Endometriosis is defined as the presence of endometrial glands and stroma outside of the uterus, most commonly over the ovaries, fallopian tubes, bladder, recto-sigmoid colon and the uterine myometrium.Endometriosis affects 5%-15% of women in the reproductive age causing pelvic or abdominal pain, infertility and occasionally rectal bleeding (if involving the bowel). Deep endometriosis is mostly defined as a single endometrial nodule, usually larger than 1 cm which is located in the vesico-uterine fold or close to the distal 20 cm of the large bowel. Those lesions usually infiltrate at least 5 mm into the tissue involved. The gold standard of diagnosis is histological proven endometriosis, usually obtained during explorative laparoscopy. Other imaging tests that aid in the diagnosis are trans-vaginal or trans-rectal sonography (TRUS), MRI & CT. Current guidelines recommends that laparoscopy with histology should be done to diagnose endometriosis. Negative (normal) laparoscopy is highly accurate in excluding endometriosis, but a positive laparoscopy (i.e. with macroscopic findings) without biopsy has a limited value. In practice, many clinicians refrain from taking biopsies due-to the risk of bowel surgery, particularly on an un-prepared bowel. Probe-based confocal laser endomicroscopy (pCLE) has been used as a GI tract endoscopy additive tool in recent years, providing in-vivo cellular-level imaging, a concept known as "optical biopsy". considering the rectal bleeding that occurs in patients suffering from bowel endometriosis, usually with a normal mucosa seen at standard endoscopy (personal data), we hypothesized that there might be histological architectural changes in the vessels or the mucosa/sub mucosa in bowel endometriosis.