Retained products of conception in hysteroscopy in a patient with breast cancer on tamoxifen

Tamoxifen is a selective oestrogen receptor modulator widely used in breast cancer treatment, with good survival rates. Its partial agonist action on other tissues such as the uterus, however, promotes the development of endometrial hyperplasia and cancer. It appears that tamoxifen does not alter the age of menopause and women may still get pregnant while on tamoxifen. We present the case of a 47-year-old Chinese woman with breast cancer on tamoxifen, who presented with one episode of heavy per vaginal bleeding after 2years of amenorrhoea. Her urine pregnancy test was negative and the ultrasound scan was suspicious for malignancy. She underwent a hysteroscopic evaluation for abnormal bleeding on tamoxifen. Histopathology confirmed products of conception. This case illustrates the importance of understanding the rise and decline of human chorionic gonadotropin in pregnancy, as well as the pivotal role of contraception despite having amenorrhoea on tamoxifen.