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PATHOLOGY OF PROSTATIC ENLARGEMENT NORMAL PROSTATE

The prostate is a retroperitoneal organ encircling the neck of the bladder and urethra and is devoid of distinct capsule.

It consists of 1. two lateral

lobes 2. a median lobe

3. one anterior & one posterior lobe encircles prostatic urethra

In normal adults; prostate weighs about 20 gm

Histologically, the prostate is a compound tubuloalveolar gland with a stroma composed of smooth muscle.

Anatomically, the prostate is closely related to the rectum, and rectal examination permits digital palpation of its posterior aspect.

Common manifestation of prostatic diseases are: Obstruction of urinary flow/ Perineal pain/ Hematuria

3 DISTINCT ZONES OF PROSTATE

CENTRAL ZONE PERIPHERAL ZONE TRANSITION ZONE

Occupies 25% of the gland’s volume. This zone consist of mucosal glands which open directly into the urethra

70% & also the major site of prostatic cacer. The glands of this zone open into the urethra via long ducts.

Which is of the medical importance bcs it is the site where most benign prostatic hyperplasia originates. Glands of this zone are sumucosal, & they open into urethra via short ducts.

1. INFLAMMATION ACUTE PROSTATITIS CHRONIC PROSTATITIS

Acute suppurative inflammation

usually following cystitis or uretheritis caused by E.coli, staphylococci or gonococci.

Chronic non-specific: due to recurrent acute attacks

Chronic specific (granulomatous): post TURP, idiopathic, TB, allergic

Prostatic diseases are classified into

I- Inflammation

II-Prostatic hyperplasia

III- Neoplasms

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2. PROSTATIC HYPERPLASIA GENERAL FEATURES TERMINOLOGY

Benign nodular enlargement or benign prostatic hypertrophy (BPH) is extremely common disorder in men over age 50 (>50%) & above 70 years (95%).

When sufficiently large, the nodules compress and narrow the urethral canal cause partial or sometimes virtually complete obstruction of the urethra

It is not a premalignant lesion

1. Prostatic enlargement: benign or malignant (a sign)

2. Prostatic hyperplasia: histological term 3. Prostatic obstruction: a clinical diagnosis 4. Bladder outlet obstruction: a urodynamic

term 5. Lower urinary tract symptoms: symptom

ETIOPATHOGENESIS

Considered to be related to the action of androgens, especially Dihydrotestosterone (DHT); a metabolite of testosterone, and the ultimate mediator of prostatic enlargement.

DHT is senthesized mainly in the stromal cells of the prostate

once it is formed it has autocrine and paracrine effect on the stromal cells and nearby epithelial cells.

DHT bind to nuclear androgen receptor and signal the transcription of growth factors

DHT is ten times more potent than androgens in combining to the androgen receptor and dissociate more slowly.

In old men with increase the estradiol level; estrogen induce an increase in androgen receptors thus making the cells more liable to DHT.

May be other factors may be involved due to heterogeniety of the disease

MORPHOLOGY

NAKED EYE MICROSCOPIC EYE

Overall, the gland is enlarged.

The periurethral part of the gland is most commonly involved.

May reaching massive size.

Firm, rubbery in consistency.

Small nodules are present throughout the gland, usually 0.5–1 cm in diameter but sometimes much larger.

Some of the larger nodules show cystic change

The glands are 1. composed of a variable mixture of hyperplastic

glandular elements & hyperplastic stromal muscle 2. are larger than normal 3. variable in size and shape 4. lined by tall epithelium that is frequently thrown

into papillary projections

The acini may contain numerous corpora amylacea.

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CLINICAL FEATURES COMPLICATIONS Mainly obstructive symptoms due to: 1. The hyperplastic nodules

compress and elongate the prostatic urethra, distorting its course.

2. Involvement of the peri-urethral zone at the internal urethral meatus interferes with the sphincter mechanism

I. Continued obstruction of the bladder :

Outflow results in gradual hypertrophy of the bladder musculature.

Trabeculation of the bladder wall develops due to prominent bands of thickened smooth muscle between which diverticula may protrude.

II. Dilatation of the bladder occurs when the compensatory mechanism fails, this results: 1. The ureters gradually dilate hydroureter,

allowing reflux of urine 2. If untreated, bilateral hydronephrosis

may develop, with dilatation of renal pelvis and calyces

3. Repeated infections predispose to the development of calculi often containing phosphates, within the bladder.

4. Urinary incontinence

3. PROSTATIC CARCINOMA GENERAL FEATURES

Age - The tumor is rare below 50 The peak incidence is between 60 and 85 years

Incidence : 241,740 (29%)

Deaths : 28,170 (9%)

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RISK FACTORS PROSTATIC INTRAEPITHELIAL NEOPLASIA (PIN)

1. Endocrinologic factors – Androgens (Orchiectomy reduce the tumor size in Prostatic carcinoma patient).

2. Racial factors- More common in African 3. Environmental factors- high fat diet, exposure to

polycyclic aromatic hydrocarbons 4. Genetic basis- familial cases (Chromosome No 1 & 10)

PIN is a precursor lesion suggests that Prostatic carcinoma may also be present.

Consists of intra-acinar proliferation of cells that demonstrate nuclear anaplasia found in a single acinus or small group of prostatic acini

GROSS APPEARANCE MICROSCOPIC Peripheral zone in the posterior lobe of the gland

Palpable in rectal exam

Multifocal, gritty and firm

Back to back arrangement of the malignant glands, lining cells show prominent nucleoli.

Invasion of stroma and perineural spaces

PRESENTING FEATURES SPREAD 1. Clinically silent & Latent carcinoma: unexpected finding in autopsy 2. Incidental carcinoma: in 15-20% of TURP done for BPH. 3. Clinical carcinoma: detected by PR, other investigations & is symptomatic. 4. Occult carcinoma: presents with features of metastases but primary is not evident.

1. Local spread: Tends to invade nerves, seminal vesicles & adjacent pelvic organs (local extension) 2. Lymphatic spread: To para-aortic, iliac LN 3. Hematogenous metastases:

most often found in the vertebrae & sacrum;

can also occur in kidneys, lungs & brain 4. Bony metastases are often osteoblastic & are associated with elevated serum alkaline phosphatase

DIAGNOSIS 1. Digital rectal examination 2. Diagnostic imaging -ultrasound, skeletal X-rays,

isotope bone scan (osteoblastic bone metastasis).

3. Cystoscopy -including transurethral resection

4. Chemical pathology –serum prostate-specific antigen (PSA>10ng/ml), Prostatic acid phosphatase (PAP), and alkaline phosphatase

5. Biopsy -transurethral resection, needle biopsy, fine-needle aspiration cytology.

GRADING STAGING

G :Gleason grades

(Score): based on the

degree of

differentiation among

the cells

S: TNM Staging