Home Education AUAUniversity Education Products & Resources Pathology for Urologists Normal Histology and Important Histo-anatomic Structures Prostatic "Capsule" and Periprostatic Tissues

Prostatic "Capsule" and Periprostatic Tissues

Image A

Image B

  • Prostate does NOT have a true capsule but an outer condensed fibromuscular band, which is an inseparable component of prostatic stroma (image A) & (image B).
    • For convenience is referred to in the literature as prostate "capsule".
      • Important boundary for staging locally aggressive prostate cancer (i.e. extraprostatic extension [EPE]).
    • This capsule is absent at prostate base and is not clearly defined at the apex, thus assessment of EPE is not amenable at these 2 sites.
  • Adipose tissue is not present within the prostate parenchyma, and involvement by prostate cancer is thus considered as EPE, including in needle biopsy.
    • Adipose tissue may be absent over large areas of radical prostatectomy specimen making pathologic evaluation of EPE difficult.

Image C

Image D

  • Cowper gland is a paired pea shaped mucinous gland situated at the urogenital diaphragm, near prostatic apex (image C).
    • Encountered rarely in needle biopsy of apex, often mingled with skeletal muscles of diaphragm.
    • Histology: Lobules of uniform acini of mucus-secreting cells (image D).
    • May mimic low-grade prostate cancer; PSA- and PSAP- in contrast to prostate cancer.