[OA-25] Diagnostic concordance of low-grade endometrial carcinoma between preoperative endometrial biopsy compared to hysterectomy specimen

Pongdanai Damyod1, Suchanan Hanamornroongruang1, Malee Warnnissorn1, Nida Jareemit2 and Natthawadee Laokolrath1

  1. Department of Pathology, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
  2. Department of Obstetrics and Gynaecology, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand

The discordant histologic grade and subtype of endometrial carcinoma (EC) between the diagnosis of endometrial biopsy and hysterectomy specimen has an impact on patient management. This study aimed to compare the diagnosis of endometrial biopsy with hysterectomy specimen and to determine the histologic factors leading to the discordant grade and subtype. A retrospective study was conducted in 187 cases of low-grade EC diagnosed from endometrial biopsy with subsequent hysterectomy, during 2018 to 2020 in Siriraj Hospital. The blinded review was performed in all discordant cases by three gynaecologic pathologists. The diagnostic accuracy of endometrial biopsy in low-grade endometrial carcinoma was 91.44%. Only 16 cases (8.56%) had discordant histologic grade and subtype. In resection specimen of these cases; twelve cases showed grade 3 endometrioid carcinoma, four cases showed high-grade components (undifferentiated EC, serous and clear cell carcinoma). In conclusion, the endometrial biopsy has a high diagnostic accuracy. However, rendering the diagnosis of high-grade carcinoma is sometimes limited by small amount of high-grade component or overlapping histomorphology of tumour subtype. The suspicion of high-grade component shoold be raised when unusual morphology is identified in biopsy specimen.

Keywords: endometrial biopsy; endometrial carcinoma; endometrioid carcinoma; low-grade