BACKGROUND: Abnormal uterine bleeding (AUB) is a universally prevalent affliction seen worldwide. However, the diagnosis and treatment of AUB are rarely straightforward due to the multifactorial aetiology, often requiring varied investigations to differentiate between functional and organic pathological lesions. A crucial diagnostic method that is beneficial is a simple endometrial biopsy procedure with an accurate histopathology diagnosis. This interventional procedure in patients suffering from AUB is warranted when medical management fails or if a radiologically suspicious endometrial thickening is seen, especially in perimenopausal and postmenopausal women. AIM: The present study was undertaken to study the histopathological spectrum of endometrial lesions, to identify the various functional/organic causes of AUB, and to highlight the importance of a definitive histopathology diagnosis in challenging cases. The study also gathered data from AUB patients diagnosed with endometrial hyperplasia/carcinoma on biopsy who underwent a hysterectomy at our institution, with the aim of examining the concordance rate between the initial biopsy diagnosis and the final diagnosis. MATERIALS AND METHODS: A retrospective three-year study was conducted in a tertiary care centre with 956 patients presenting with AUB who underwent endometrial sampling, dilation and curettage (D&C)/Pipelle aspiration as a diagnostic work-up. RESULTS: Of the 956 endometrial samples received, 106 were found to be inadequate for diagnosis, reducing the sample size to 850. Data analysis showed that perimenopausal women had the highest incidence of AUB (379/850
44.5%). The incidence of functional and organic causes of AUB was 73.9% (628/850) and 26.1% (222/850), respectively. The most common functional cause of AUB was disordered proliferative endometrium (DPE) (235/628
27.7%), followed by proliferative endometrium with 155/850 cases (18.2%). The most common organic lesion was benign endometrial polyp (102/850
12%). It was followed by non-atypical hyperplasia (55/850
6.5%) and then atypical endometrial hyperplasia/endometrial intraepithelial neoplasia (AEH/EIN) (41 cases, or 4.8%). Of the 22 cases of endometrial carcinomas, 81.8% were of the endometrioid type, followed by 9.2% cases of carcinosarcoma, and the remaining were clear cell carcinoma (4.5%) and serous carcinoma (4.5%). CONCLUSION: Endometrial sampling, D&C/Pipelle aspiration is an essential gynaecological investigation in the evaluation of AUB. An accurate histopathology diagnosis, especially in endometrial malignancies, brings clarity and sets the stage for effective treatment strategies.