Prostatic mucinous carcinoma (MC) and prostatic signet ring cell carcinoma are two variants of prostate cancer. MC has a higher overall survival time among all variants, while signet ring cell carcinoma is associated with lower survival time relative to other carcinomas. Only a small proportion of prostatic MC may contain signet ring cells. Over the last several decades there were only 12 patients that were documented in two studies.We report on a 64-year-old man who was diagnosed with prostatic MC after he received a robotic-assisted laparoscopic radical prostatectomy in the West China Hospital. After robotic-assisted laparoscopic radical prostatectomy, the patient underwent three successive transurethral resections of bladder tumors. Pathological examination of the first transurethral resection of bladder tumors specimen indicated that the neoplasm was prostatic MC that had metastasized to the urinary bladder. The subsequent two transurethral resections of bladder tumors indicated the presence of prostatic mucinous carcinoma with signet ring cells.This case report aimed to share the management experience, raise awareness, and highlight the importance of multidisciplinary cooperation of prostatic mucinous carcinoma with signet ring cells.©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.