A 43-year-old female was admitted to the Hospital of Chengdu University of Traditional Chinese Medicine on March 13th 2018 due to hematuria for 6 days and inability to urinate spontaneously for 1 day. 6 days ago, the patient discharged visible hematuria without any obvious cause and she denied frequent and urgent micturition, dysuria, lumbago, fever, nausea and vomiting. 1 day ago, the patient presented at a grade three A hospital emergency department for catheterization; the urinary system ultrasound revealed that there was a echo mass measured 6.5cmx3.0cm(considering blood clots) around the urinary catheter. She had a history a myomectomy(the details were not available). At admission, the indwelling catheter was in the right place and the patient manifested with dark red urine, occasional bilateral lumbago and lower abdominal dull pain. At that time, she was in her period without chills, fever, nausea and vomiting. The physical examination showed stable vital signs with suspicious positive percussion pain in two kidney regions and mild percussion pain in the bladder region. Preliminary diagnoses were cause of hematuria to be investigated: (1) urinary tract infection (2) urinary tumors (3) other. Relevant examinations after admission were conducted. Urinalysis (clean midstream urine) were: erythrocytes 2189.2/uL, leukocytes 121.4uL,and leukocyte esterase 1+. No abnormalities were found in coagulation tests. Hepatic and renal function showed uric acid 373umol/L with no other abnormalities. There was no abnormality of tumor markers CA125:78.6U/ml, AFP, CEA, FERRITIN, pro- grp, nse, cefra21-1, ca72-4, ca15-3, ca19-9, ca50, CA242, SCCA, HE4, pro ROME, and post ROME. 3 times of urine exfoliative cytology smear examinations were listed as follows: a large number of exfoliative urinary tract epithelial cells were found and some nuclear heterogeneity were shown at the first time; tumor cells were found, which tended to be tumor cells at the second time(Figure 1) and specific types of cell blocks was to be made (Figure2) for immunocytochemical testing; a small number of degenerated heterogeneous epithelial cell clusters, and more neutrophils were seen at the third time. The immunophenotype of the cell blocks slides revealed tumor cells Ki-67 (+, <1%), EMA (+), CK7 (+), vimentin (+) (Figure 3), CD10 (+) (Figure 4) , P40 (-), P63 (-), S100P (-), suggesting endometrial glands and stromal cells, excluding malignant tumor cells. Besides, pathological section of prolapsed tissue in the bladder showed that there were scattered small and heterotypic cell clusters in blood clots and degenerative necrotic tissues. Immunophenotype: Ki-67 (+, <2%), EMA (+), Vimentin (+), CK7(+), CD10(+), ER(+), PR(+), Syn(-), CD56(-), S-100(-), CD99(-), CD117(-) , P63 (-), P40 (-), suggested degenerated endometrial glands and stroma. CT urography (CTU) indicated that there were few low-density filling defects in the bladder in the delayed phase, and the shape was irregular, considering the possibility of blood clots. Cystoscopy revealed a depressed change at the posterior wall of the bladder at its filling state, which seems to be connected to the peritoneum, and the surrounding bladder mucosa and the other bladder walls in the bladder triangle area were normal. Hematuria disappeared at the end of menstruation, and the urine routine re-examination revealed occult blood 1+Ca25cell/uL. Taking medical history and pathological examination into consideration, the cause of hematuria may be vesicouterine fistula (VUF).