Evaluation of Preoperative Endometrial Biopsy Accuracy and Etiological Distribution in Abnormal Uterine Bleeding Using the PALM–COEIN Classification

Rulin Deniz¹Yakup Baykus¹Alihan Tığlı¹Muhammed Bora Uzuner¹Nazli Sener¹Yasemin Ercan Değirmenci¹Güzide Ece Akıncı^1,2Erdem Gürkan²Oğuzhan Karakoç²Mustafa Ata Aydin³Elif Emre⁴SULEYMAN AYDİN^5*

• ¹Bandirma Onyedi Eylul Universitesi, Bandirma, Türkiye
• ²TC Saglik Bakanligi Bandirma Egitim ve Arastirma Hastanesi, Bandirma, Türkiye
• ³Gazi Universitesi Tip Fakultesi, Ankara, Türkiye
• ⁴Firat Universitesi Tip Fakultesi, Elâzığ, Türkiye
• ⁵Firat University, Elazig, Türkiye

ABSTRACT ObjecƟve: Abnormal uterine bleeding (AUB) is one of the leading causes of gynaecological consultaƟons and indicaƟons for hysterectomy. The aim of this study is to determine the distribuƟon of aeƟological causes in paƟents undergoing hysterectomy due to AUB according to the FIGO PALM-COEIN system and to evaluate the diagnosƟc concordance between preoperaƟve endometrial biopsy (EB) results and final hysterectomy pathology. Methods: This retrospecƟve, descripƟve and analyƟcal study included 296 paƟents who underwent hysterectomy due to AUB at Bandırma Onyedi Eylül University Hospital between 2020 and 2025. The paƟents' demographic data, clinical characterisƟcs, and histopathological results were examined from hospital records. The causes of AUB were categorised according to the PALM-COEIN system (Polyps, Adenomyosis, Leiomyoma, Malignancy; Coagulopathy, Ovulatory, Endometrial, Iatrogenic, Unclassifiable). The concordance of preoperaƟve EB results with final pathology was analysed using sensiƟvity, specificity, posiƟve/negaƟve predicƟve values, the Kappa coefficient, and ROC analysis (AUC). Results: The mean age of the paƟents was 48.2 ± 6.9 years. According to the PALM-COEIN classificaƟon, structural causes (PALM) were the most common eƟology, with leiomyomas (35.5% isolated, 59.8% total) forming the predominant group. The rate of postmenopausal bleeding was determined to be 28.0%. Regarding concordance between preoperaƟve EB and final pathology, EB demonstrated high specificity but limited sensiƟvity, parƟcularly for focal lesions. For AEH+ (atypical endometrial hyperplasia and above), sensiƟvity was 22.2%, specificity was 99.6%, and AUC was 0.609; for endometrial polyps, sensiƟvity was 30.6%, specificity was 83.0%, and AUC was 0.568. Overall agreement between biopsy and final pathology (Kappa) was low to moderate, and ROC analysis indicated limited discriminatory ability across subgroups. Conclusion: Among paƟents undergoing hysterectomy for AUB, structural pathologies, parƟcularly leiomyomas, consƟtute the primary reason for hysterectomy. Although preoperaƟve EB is successful in ruling out pathologies, it may be insufficient in detecƟng focal lesions and some premalignant condiƟons due to its low sensiƟvity. Therefore, EB results should be supported by advanced diagnosƟc imaging methods, especially when clinical suspicion exists during the decision-making process for hysterectomy. Keywords: Abnormal Uterine Bleeding, Hysterectomy, Endometrial Biopsy, PALM-COEIN, DiagnosƟc Accuracy.