Repeated Recurrences of Mucinous Prostate Carcinoma With Signet Ring Cells in the Urinary Bladder After Robotic-assisted Laparoscopic Radical Prostatectomy: a Case Report and Literatures Review

Background: Mucinous prostate carcinoma (PCa) and signet-ring-cell PCa are two rare variants of prostate cancer, but the transformation of mucinous PCa into mucinous PCa with signet ring cells was extremely uncommon, little data of therapy was available. Case presentation: We reported such a case that a man was pathologically considered as mucinous PCa after receiving transurethral resection of the prostate, then he underwent robotic-assisted laparoscopic radical prostatectomy (RARP), the pathological diagnosis was mucinous PCa (pT2cN0M0), without any adjuvant therapies, the man had received regular follow-up with serum total prostate-specific antigen level <0.003 ng/ml. Nevertheless, he received transurethral resection of bladder tumor (TUR-BT) at 13 months, 22 months and 31 months after RARP, respectively, the first TUR-BT specimens was mucinous PCa, where the two other present mucinous PCa with signet ring cells. Conclusions: We reviewed the literatures and discussed the differential diagnosis, immunohistochemistry, prognosis of this rare carcinoma, emphasized the rarity of the histological change and demanded fundamental research clarifying the confusion of this change, which may be helpful to search for therapeutic targets and improve prognosis.