Discussion And Conclusion
In 1967, Gutierrez first reported ectopic prostatic tissue in English literature. Although more cases have been reported since, its pathogenesis remains unclear. The mechanism of ectopic prostatic tissue mainly includes three theories: embryo development residual, embryo submucosal migration, and metaplasia changes caused by chronic inflammation[4–5]. The prostate-type glands are seen in the trigone during embryogenesis[6], consistent with the most common location of ectopic prostatic tissue in the bladder trigone. Importantly, the ectopic prostatic tissue is not different from normal prostate tissue histologically or immunohistochemically. Our case also revealed that the prostate glands were submucosal, supporting the theory that ectopic prostate tissue is a continuation of the embryonic structures[3].
Ectopic prostatic tissue usually presents as a single, smooth-surfaced, firm nodular, papillary mass on cystoscopy. It may appear as a homogeneous mass in the bladder on sonography or CT, with few characteristics different from those of typical urothelial carcinomas. Ectopic prostate tissue is a benign lesion that mainly depends on the pathological diagnosis. Even on a preliminary biopsy of the bladder mass, the ectopic prostate tissue can be easily confused with bladder tumors. Similar to our case, pathological examination of cystoscope biopsy is considered as NA, which typically appears as papillary projections protruding into the bladder lumen on cystoscopy. Histologically, NA may be simulated to various malignant tissue elements such as prostatic adenocarcinomas[7]. Immunohistochemically, NA is variably positive for AMACR and CD10 and may be positive for PSA and PSAP in the focal lesion, while being negative for p63[7]. Because of these similar characteristics, ectopic prostate tissue may be misdiagnosed as an NA. The secretory and basal cells of the prostate glands express PSA, PSAP, P63, 34βE12, and CD10, but P63, 34βE12, and CD10 are not expressed in carcinomatous prostates[8]. Based on this observation, the tumor origin in the prostate and NA can be distinguished. Besides, other benign lesions of the bladder that could be misdiagnosed as malignant should also be identified.
Table 1. Overview of case reports of ectopic prostate tissues located in the bladder.
To the best of our knowledge, ectopic prostate tissues are arising in the adult male of all ages. All cases of intravesical ectopic prostate tissues were completely excised by transurethral resection reported in English literature on PubMed (Table 1). However, in our case, the bladder occupying lesion was completely resected under laparoscopic pneumovesicum, which was described as intravesical surgery using pneumovesicum in urology[9]. The pneumovesicum can provide enough space for operation, and laparoscopy has the characteristics of magnification that is convenient for doctors to accurately remove the tumor tissue. It could definitively diagnose the tissue type and avoid misdiagnosis, which, to the best of our knowledge, has not been previously reported. If the intravesical lesion is small, transurethral resection maybe brings less trauma to the patient compared with resection through laparoscopic pneumovesicum. All case reports of ectopic prostate tissues located in the bladder are not recurrence in the follow-up(Table 1). Although postoperative prognosis is good, it may be recurrent[10]. So far, no malignant cases of recurrent ectopic prostate tissue have been reported. However, cancer arising in the ectopic prostatic tissue of the bladder has been reported[11]. Therefore, regular examination and follow-up are crucial for patients with this condition.
The limitation of this case is that benign lesions should be considered when the bladder occupying lesion does not look malignant. By selecting a more suitable surgical resection method, can be reduced the surgical trauma of patients. In addition, the short follow-up time is one of the limitations.