Persistent Müllerian Duct Syndrome (PMDS) is a rare autosomal recessive disorder of sex development characterized by the presence of fallopian tubes, uterus and upper one-third of the vagina in individuals with XY genotype and normal male phenotype. The main complications of PMDS are infertility and the rare risk of malignant degeneration of both testicular and Müllerian derivatives. We report the case of a 49-year-old man who, during repair of an incisional hernia, was incidentally found to have a uterine-like structure posterior to the bladder. In the past at the age of 18 months, he had undergone bilateral orchidopexies for bilateral cryptorchidism. The intraoperative decision was to preserve the uterine-like structure and make a more accurate diagnosis postoperatively. Evaluation revealed an XY chromosome and imaging consistent with PMDS. The patient was informed about the risk of neoplastic transformation of the residual Müller ducts and was offered surgical treatment, which he declined. Subsequent follow-up imaging studies, including testicular and pelvic ultrasound, were negative for findings suggestive of malignant testicular and Mullerian derivative degeneration. A review of the international literature showed that, when a decision is taken to remove the Mullerian derivatives, laparoscopy and especially robotic surgery allow for the successful removal of Müllerian derivatives. Whenever the removal of these structures is not possible or the patient refuses to undergo surgery, it is necessary to inform the patient of the need for adequate follow-up. Patients should undergo regular pelvic imaging examination and MRI might be a better method for that purpose.