Fever and leukemoid reaction in bladder cancer: A case report.

The current study presented and analyzed the clinical data of a patient who had bladder cancer complicated by a leukemoid reaction, aiming to discuss the diagnosis, treatment and underlying mechanism of leukemoid reactions in bladder cancer. The patient had a significant smoking history and underwent six transurethral resections of bladder tumors between August 2016 and October 2023. Pathological diagnosis deteriorated from low-grade papillary urothelial carcinoma (UC) to high-grade papillary urothelial carcinoma. The patient did not adhere to regular cystoscopy or routine follow-up cystoscopy and declined radical cystectomy. The most recent computed tomography scan revealed the following: i) Multiple tumors in the bladder; ii) invasion at the bilateral ureteral orifices; iii) dilation of the bilateral renal pelvis and ureters; and iv) multiple lymphadenopathies in the pelvis and along the right iliac artery. Following cystoscopy examination and urethral catheter placement, the patient's creatinine level gradually decreased; however, there was an increase in body temperature and white blood cell count. The patient was diagnosed with a leukemoid reaction secondary to bladder cancer. The patient refused a bone marrow biopsy and palliative care was administered. The patient passed away in October 2023. Cases of bladder cancer complicated by a leukemoid reaction are rarely reported clinically. Even after surgical resection, the prognosis remains poor. Monitoring granulocyte-colony stimulating factor (G-CSF) levels in blood can aid in predicting the condition of the patient's health. Blocking the G-CSF signaling pathway might serve as a future therapeutic target for bladder cancer complicated by a leukemoid reaction.