Correlation Between Hysteroscopic Findings and Histopathological Evidence of Chronic Endometritis in Reproductive Age Women with Gynecological Disorders.

STUDY OBJECTIVE: To correlate 12 predefined hysteroscopic endometrial features with histopathological plasma cell grading (H&E) and dual immunohistochemical expression of CD138 and MUM-1 in reproductive-age women presenting with abnormal uterine bleeding (AUB), infertility, or recurrent pregnancy loss (RPL) at a tertiary care centre in India, and to evaluate whether chronic endometritis (CE) prevalence differs across these three clinical indications. DESIGN: Prospective cross-sectional observational study. SETTING: Tertiary care academic hospital, New Delhi, India. PATIENTS: Seventy consecutive women of reproductive age presenting with AUB (n=40, 57.1%), infertility (n=22, 31.4%), or RPL (n=8, 11.4%), fulfilling predefined eligibility criteria, who underwent hysteroscopy with directed endometrial biopsy over 1.5 years. INTERVENTIONS: Assessment of 12 predefined hysteroscopic features between days 7-11 of the menstrual cycle, followed by directed endometrial biopsy subjected to immunohistochemical (IHC) expression of CD138 (syndecan-1, a surface marker of fully differentiated plasma cells) and MUM-1 (IRF4, a nuclear marker active across late B-cell differentiation into plasma cells). MEASUREMENTS AND MAIN RESULTS: CD138 positivity was identified in 90.0% of participants (low-grade 60.0%; high-grade 30.0%); MUM-1 in 74.3% (low-grade 50.0%; high-grade 24.3%). On H&E, Grade 1 plasma cell infiltration (PC-1) was present in 40.0% and Grade 2 in 14.3%. Micropolyps were significantly associated with Grade 2 plasma cell infiltration (PC-2) (p=0.040; OR=4.89, 95% CI 0.96-24.97) and CD138 high positivity (p=0.019; OR=3.63, 95% CI 1.20-10.94). Hysteroscopic evidence of endometrial hyperplasia correlated with PC-2 (p=0.027; Cramér's V=0.284). Localized hyperemia was associated with MUM-1 low positivity (χ²=8.70, df=2, p=0.013). CE prevalence did not differ significantly across clinical subgroups (all p>0.05). No granulomatous endometritis was identified. CONCLUSIONS: CE is common and equally prevalent across AUB, infertility, and RPL presentations at this centre. Micropolyps and endometrial hyperplasia are the most informative hysteroscopic predictors of high-grade CE. CD138 is the more sensitive marker; MUM-1 adds complementary value by identifying earlier-stage B-lineage activation. Hysteroscopy with directed biopsy and dual CD138/MUM-1 immunohistochemistry is the recommended diagnostic approach.