Detection of Endometrial Nerve Fibres – a Novel Technique to Diagnose Endometriosis

Abstract

Purpose To detect the presence of nerve fibres by immunohistochemical staining method using anti-PGP9.5 antibody in the eutopic and ectopic endometrium of patients with endometriosis. Methods Patients presenting with pelvic pain and/or infertility were subjected to premenstrual endometrial biopsy during laparoscopy. Thirty patients diagnosed with endometriosis formed the study group and 30 patients with no histological/laparoscopic evidence of endometriosis formed the control group. Endometrial biopsy tissue of all the 60 patients along with biopsy from endometriomas and peritoneal implants of confirmed cases of endometriosis (n = 30) were subjected to immunohistochemical staining to detect nerve fibres. Results Neural elements were observed in the eutopic endometrium of 24/30 cases (80%) in the study group and in none of the controls (p<0.01), while the sections from endometriomas and peritoneal implants demonstrated nerve fibres in all the 30 cases of confirmed endometriosis. The nerve fibres in the endometrial tissue were heterogeneously distributed and were sparse in number with an observed density of <1 nerve fibre/mm2 while they were present in large numbers in the ectopic endometrium (10 ± 3 nerve fibre/mm2). Also, the presence of nerve fibres in the eutopic and ectopic endometrium positively correlated with the intensity of pain (p<0.001). Conclusion Eutopic endometrium exhibited positivity for nerve fibres in 24 out of 30 cases of proven endometriosis, though the density of nerve fibres was low as compared to that reported in a few studies.