Prostate gland

The prostate gland and its surrounding structures. (WC/NCI)

The prostate gland adds juice to the sperm. In old men it creates a lot of problems... nodular hyperplasia (commonly called BPH or benign prostatic hyperplasia) and cancer (usually adenocarcinoma).

Prostate cancer is such a big topic it is dealt with in its own article.

The female homologue of the prostate gland is considered to be Skene's gland.

Normal prostate gland

Anatomy

Divided into three zones:

1. Peripheral zone - posterior aspect, palpable with digit.
   • Classic location for cancer.
2. Central zone - considered resistant to disease.
3. Transition zone - usual location for nodular hyperplasia.

Histology

• Glands have two cell layers (similar to glands in breast).
  • Second cell layer may be difficult to see (like in breast).
• Epithelium in glands is "folded" or "tufted".
  • Very important - helps to differentiate from Gleason pattern 3.
• Luminal epithelium often clear cytoplasm.
• Single nucleus.

Benign normal:

• Corpora amylacea.
  • Round/ovoid-eosinophilic bodies -- with laminations (layered appearance).
  • In gland lumina.
  • Usually in benign glands - but cannot be used to exclude cancer.
  • Very common.
  • These should be differentiated from eosinophilic proteinaceous debris - which is associated with cancer.

Negatives:

• No nucleoli present (if you see nuclei think: cancer, HGPIN, reactive changes, basal cell hyperplasia).
• No mitoses - these are uncommon... even in high grade prostate cancer.

Notes:

• Tufted epithelium is a strong indicator of benignancy; however two uncommon prostate cancer variants typically have tufted epithelium:
  • Pseudohyperplastic adenocarcinoma.
  • Foamy gland carcinoma.

Images

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  Benign prostate with corpora amylacea - low mag. (WC/Nephron)

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  Benign prostate with corpora amylacea - high mag. (WC/Nephron)

IHC of normal prostate

Normal prostate:

• AMACR -ve (mark epithelial cells).
• CK5/6 +ve, p63 +ve, HMWCK +ve (mark basal cells).
• PSA (prostate-specific antigen) +ve, PSAP (prostatic-specific acid phosphatase) +ve.

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Staining slightly abnormal - morphology not definitely abnormal

COMMENT:
Very focal AMACR staining is seen; this is interpreted as negative, in the
context of no definite cytologic changes.  The basal cells appear to be 
preserved in all of the tissue sampled.

Compatible with previous biopsy

COMMENT:
Siderophages are seen in several cores; this is compatible with the history 
of a previous biopsy.

Other accessory glands

Bulbourethral gland

• AKA Cowper's gland.

Main article: Bulbourethral gland

Seminal vesicles

Main article: Seminal vesicles

Specimens

• Prostate core biopsy - done transrectal.
• Prostate chips (from a transurethral resection of the prostate, abbreviated TURP) - usu. done for nodular hyperplasia of the prostate gland; may be done in the context of obstructing cancer.
• Radical prostatectomy - includes the seminal vesicles.
• Radical cystoprostatectomy - includes the urinary bladder and seminal vesicles.

Approach

• Know the common diagnoses well.
• Core biopsies - scan the slides with the 10x objective.

Common diagnoses

• Benign.
  • Atrophy - may resemble adenocarcinoma - typically not reported.
  • Adenosis - may resemble adenocarcinoma - typically not reported.
• Prostate adenocarcinoma.
• HGPIN (high-grade prostatic intraepithelial neoplasia) - prostate adenocarcinoma precursor lesion.
• ASAP (atypical small acinar proliferation) - used if you have a few abnormal appearing glands... but can't decide between prostate adenocarcinoma & benign.
• Chronic inflammation.
• Acute inflammation - can result in an elevated PSA and may have prompted the biopsy you're looking at.
• Nodular hyperplasia of the prostate; AKA benign prostatic hypertrophy (BPH).
  • Not diagnosed on needle biopsies.
  • BPH is technically incorrect -- the process is a hyperplasia.
    • Hyperplasia = proliferation of cells, hypertrophy = enlargement of cells.
      • How to remember? A. Prostate... hyperPlasia.

Clinical history

Main article: Prostate specific antigen

• PSA (serum).
  • >10 ng/mL worrisome for prostate cancer.
  • Normal is age dependent - increases with age, usu. cut-off ~ 4 ng/mL.
• HIFU = High Intensity Focused Ultrasound - an ablation procedure for prostate cancer.

Benign changes and remnants

Adenosis of the prostate gland

• AKA atypical adenomatous hyperplasia of the prostate gland (or atypical adenomatous hyperplasia).

Main article: Adenosis of the prostate gland

Basal cell hyperplasia of the prostate

Main article: Basal cell hyperplasia of the prostate

Atrophy of the prostate

• AKA atrophy.
• AKA prostatic atrophy.
• AKA atrophy of the prostate gland.

Main article: Atrophy of the prostate gland

Mesonephric remnant of the prostate gland

Main article: Mesonephric remnant of the prostate gland

Benign conditions

Prostatic nodular hyperplasia

• AKA nodular hyperplasia of the prostate.
• AKA benign prostatic hyperplasia (abbreviated BPH).
• AKA benign prostatic hypertrophy.
  • This is a misnomer. It is not a hypertrophy.

Main article: Nodular hyperplasia of the prostate

Acute inflammation of the prostate gland

Prostate gland
External resources
EHVSC	10176

• AKA prostate gland with acute inflammation.

General

• A may lead to an increase in the PSA and prompt biopsy.

Note:

• "Prostatitis" is considered a clinical diagnosis.
  • Cases are signed out as "acute inflammation".
    • Some pathologists do not comment on the presence (or absence) of inflammation.

Microscopic

Features:

• Neutrophils within the glands, between the epithelial cells or within the stroma - key feature.
• +/-Chronic inflammation (lymphocytes) within the surrounding stroma.

DDx:

• Prostatic infarction.

Image

• 

  Prostate with acute inflammation. (WC/Nephron)

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G. PROSTATE, LEFT LATERAL SUPERIOR, BIOPSY:
- BENIGN PROSTATE TISSUE;
- FOCAL ACUTE INFLAMMATION. 

G. PROSTATE, LEFT LATERAL SUPERIOR, BIOPSY:
- BENIGN PROSTATE TISSUE;
- FOCAL ACUTE AND CHRONIC INFLAMMATION. 

Chronic inflammation not otherwise specified

General

• Common.
• Non-specific finding.
• Etiology usually not apparent on histomorphology.

Microscopic

Features:

• Lymphocytes within the glands, between the epithelial cells or within the stroma - key feature.

Notes:

• Rare scattered lymphocytes are common, especially in the central portion of the gland.
• "Focal" one field with a 2.2 mm diameter involved.

Image

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  Prostate with chronic inflammation. (WC/Nephron)

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G. PROSTATE, LEFT LATERAL SUPERIOR, BIOPSY:
- BENIGN PROSTATE TISSUE;
- FOCAL CHRONIC INFLAMMATION. 

F. PROSTATE, RIGHT MEDIAL MIDZONE, BIOPSY:
- BENIGN PROSTATE TISSUE;
- CHRONIC INFLAMMATION. 

Note:

• Opinion is divided on whether this finding should be reported.
  • Advocates for reporting inflammation say "[i]t is just reporting what you see and may explain the bump in PSA."
  • Naysayers opine that "[i]t may provide false assurance that no cancer is present."

Granulomatous prostatitis

Main article: Granulomatous prostatitis

Prostatic infarct

• AKA prostatic infarction.

General

• Rare < 0.1% of core biopsies.
• Can mimic cancer - urothelial carcinoma.
• Prostate usually large.

Microscopic

Features:

• Classic findings of necrosis:
  • Karyolysis (loss of nuclei), karyorrhexis (frag. of nuclei), pyknosis (small shrunken nuclei).
• +/-Squamous metaplasia of prostate gland epithelium.

Notes:

• Corpora amylacea - help... call it benign.
• Glands maintain normal spacing.

DDx:

• Urothelial carcinoma with squamous differentiation.

Image:

• Prostatic thrombosis (sciencephoto.com).

Preneoplastic changes and atypical changes

High-grade prostatic intraepithelial neoplasia

• Abbreviated as HGPIN.
• May be referred to as prostatic intraepithelial neoplasia, abbreviated PIN.

Main article: High-grade prostatic intraepithelial neoplasia

Atypical small acinar proliferation

• Abbreviated ASAP.
• AKA suspicious for carcinoma.
  • ASAP is preferred as it does not contain the word carcinoma and, thus, cannot be misread as carcinoma, i.e. positive for malignancy.

Main article: Atypical small acinar proliferation

Prostate cancer

Main article: Prostate cancer

This is a big topic that is dealt with in its own article.

See also

• Urothelium.
• Genitourinary pathology.