Abstract Background Management of a bladder tumor during pregnancy is an uncommon clinical situation. Leiomyosarcoma of the urinary bladder is a rare histological type of bladder tumor and a rare secondary cancer in survivors of retinoblastoma (RB). However, there has been no report of RB-associated bladder leiomyosarcoma during pregnancy. Case presentation A 37-year-old pregnant woman with a medical history of RB in infancy presented with gross hematuria at the 17th week of gestation. Cystoscopy revealed a 40-mm papillary tumor on the left lateral wall of the urinary bladder. At the 25th week of gestation, she underwent transurethral resection of the bladder tumor, and the pathological diagnosis was bladder leiomyosarcoma with loss of RB1 expression. At the 31st week of gestation, she gave birth by caesarean section. One month after the delivery (to allow for involution of the uterus), she underwent partial cystectomy, and the specimen contained no residual leiomyosarcoma tissue. Conclusions We have reported a case of RB-associated bladder leiomyosarcoma that was successfully treated during and after pregnancy.
