Diagnosis of endometriosis by detection of nerve fibers using protein gene product 9.5 immunohistochemistry

Abstract

Introduction: Endometriosis is a benign, chronic, multifactorial, debilitating gynecological disease defined by the presence of ectopic foci of endometrial glands and stroma. Diagnostic laparoscopy and histopathological study of hysterectomy specimens are the definitive tool for diagnosis which carries associated risks. The objective of this study is to analyze the presence of protein gene product 9.5 (PGP9.5) antibody-positive nerve fibers by immunohistochemistry (IHC) in endometrial biopsy samples and endometriotic lesions in suspicious cases of endometriosis. Materials and Methods: This was a case–control study carried out in a tertiary care center. It comprised of cases of endometriosis interna (adenomyosis), endometriosis externa (endometriosis), and age- and parity-matched women without endometriosis taken as control. Clinically/radiologically diagnosed cases of endometriosis and those undergoing laparoscopy for infertility with confirmation after histopathology were included in the study. Endometrial biopsy samples were subjected to IHC using PGP9.5 antibody and examined for The presence of nerve fibers. Statistical analysis was done using SPSS software, and analysis of nerve fibers stained by PGP9.5 was done by the Kruskal–Wallis test. Results: A total of 60 cases are included in this study broadly divided into three groups (30 women with adenomyosis, 10 with endometriosis externa, and 20 women without endometriosis). Majority (26/30 = 65%) belonged to the third to fourth decade of life with pain being the most specific symptom. Small nerve fibers were noted in endometrial foci of the endometriosis cases but not in women without endometriosis (P = 0.001). Conclusion: The presence of nerve fibers can be taken as a novel marker of clinical endometriosis, and thus, it could replace hysterectomy as a definitive modality for diagnosing endometriosis.