Adenocarcinoma in ectopic prostatic tissue at the trigone of urinary bladder

Introduction Ectopic prostatic tissue is prostatic tissue located distant from the prostate gland. Although its existence is not uncommon, the occurrence of adenocarcinoma in ectopic prostatic tissue is rare. Case presentation A 68‐year‐old man was suspected to have a nodular‐type tumor in the bladder trigone and a tumor in the prostate based on magnetic resonance imaging and cystoscopy results. Transurethral tumor resection and transrectal prostate needle biopsy revealed the coexistence of ectopic prostatic adenocarcinoma in the bladder trigone and low‐risk orthotopic prostate cancer. Four years later, the tumor evolved to intermediate‐risk prostate cancer during active surveillance, and the patient underwent prostatectomy with resection of the bladder trigone. Pathology indicated no residual ectopic prostatic tissue or adenocarcinoma at the bladder trigone. Conclusion Adenocarcinoma in ectopic prostatic tissue is very rare; however, when found, the possibility of concurrent cancer in the prostate gland should be considered.