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Ectopic prostatic tissue in the perineum
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  1. Bishoy Hanna1,2,
  2. Anna McNaught3,
  3. Amanda Chung1,4,5 and
  4. Venu Chalasani1,5,6
  1. 1Department of Urology, Northern Beaches Hospital, Frenchs Forest, New South Wales, Australia
  2. 2Department of Urology, Nepean Urology Research Group, Kingswood, New South Wales, Australia
  3. 3Department of Radiology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
  4. 4Department of Urology, Macquarie University Hospital, Macquarie University, New South Wales, Australia
  5. 5Department of Urology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
  6. 6Department of Urology, The University of Sydney, Camperdown, New South Wales, Australia
  1. Correspondence to Dr Bishoy Hanna; bishoy.hanna{at}icloud.com

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Description

Ectopic prostatic tissue is rare and <50 cases have been reported in the literature. The most common reported location is the trigone of the urinary bladder and rarely at the bladder neck or periurethral location.1 Postulated aetiology of prostatic ectopia include the persistence of prostatic tissue during embryogenesis, or metaplasia of the urinary epithelium due to chronic inflammation, or even migration of prostatic stem cells.2–4

We present a 72-year-old man with a 1-week history of progressively worsening obstructive lower urinary tract symptoms culminating in overt acute urinary retention of >1 L. This was acutely managed with an indwelling catheter. His medical history included hypertension and gastro-oesophageal reflux. His international prostate symptom score was 6 prior to the onset of symptoms, and a digital rectal examination revealed a mildly enlarged benign prostate. The prostate-specific antigen (PSA) was 7.0 µg/L. MRI of the prostate showed Prostate Imaging Reporting And Data Systems 3 lesions along with a solid lesion distal to the prostatic apex in the midline, completely separate from the prostate (figure 1). This lesion was smooth, well circumscribed and appeared benign. A cystoscopy revealed no intraluminal urethral lesions with a mildly enlarged, non-occlusive prostate and unremarkable bladder. The patient underwent a systematic transperineal prostate biopsy with additional cores taken corresponding to the extraprostatic perineal lesion on MRI. Histopathology showed benign prostatic hyperplasia of the extraprostatic perineal lesion and Grade Group 2 adenocarcinoma within the prostate.

Figure 1

MRI of the prostate with (A) sagittal T2 weighted (T2W) and (B) coronal T2W images showing the prostate gland (solid arrows), ectopic prostate tissue (solid arrowhead) and urethral sphincter (open arrowhead).

Ectopic prostatic tissue has been described widely throughout the body, most commonly in the urethra, seminal vesicles, epididymis, testis and urinary bladder.5–10 Clinically, they present with lower urinary tract symptoms; haematuria being most common but obstructive symptoms such as urinary frequency and retention also feature. Outside of the genitourinary system, ectopic prostatic tissue is a distinctly uncommon phenomenon but has been reported in the spleen, rectum and uterine cervix, as well as in ovarian teratomas.11–13

Various aetiologies have been postulated for ectopic prostate tissue. In the prostatic urethra and bladder trigone, this may represent a vestigial remnant from embryogenesis, while for other sites metaplasia and aberrant embryogenesis via ‘migration’ or ‘misplacement’ of prostate glands have been described.10 12

Generally if the lesion is asymptomatic and benign, resection is not indicated. However, it should be noted that this tissue will be a source of PSA. Primary adenocarcinoma arising from ectopic prostatic tissue has been reported.14 15 A 5-mm cystic bladder lesion was found to be prostatic adenocarcinoma on resection (Gleason 4+3=7).14 Furthermore, a report of ectopic prostate cancer (Gleason 4+3=7) in the seminal vesicles surrounded by normal prostatic glands with a transrectal prostate biopsy showing no intraprostatic cancer was managed with radiotherapy and hormonal treatment.15 Ectopic prostatic tissue is a rare entity but significant as it may be a site for primary prostate cancer and will cause a persistently raised PSA following a radical prostatectomy.

Learning points

  • Ectopic prostate tissue (EPT) distal to the apex of the prostate is a rare entity, as it is commonly located on the trigone of the bladder.

  • MRI is a sensitive imaging modality for detecting EPT.

  • It may be a rare cause of persistently raised prostate-specific antigen following a radical prostatectomy.

  • It should be considered in the differential diagnosis of a palpable lump on digital rectal examination.

References

Footnotes

  • Contributors BH: primary author who gathered the relevant information for the case, reviewed the literature and wrote the manuscript. Furthermore, he coordinated input from the rest of the research team for revisions and submission. AMN: provided valuable insights on the radiological images ensuring suitable quality and accurate interpretation. Furthermore, she was involved in reviewing the final manuscript. AC: provided valuable insights on the case, including the up to date evidence in the area, and reviewed the manuscript. VC: the primary clinician for the patient at the centre of the case. He gathered, interrupted case material and reviewed the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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