Pathology > Study Images > Male Genitals > Prostate > Benign Conditions
Objectives Anat & Hist Benign Neoplasms

II. Benign Conditions


After completing this section you will be able to:

  • describe the relationship between nodular prostatic hyperplasia and sex hormones
  • describe the clinical and histologic features of nodular hyperplasia
  • describe the relationship between nodular hyperplasia and carcinoma of the prostate
  • list the possible complications of nodular hyperplasia and explain how they occur

Nodular Hyperplasia (Prostatic Hyperplasia)

Nodular hyperplasia (the use of the term benign prostatic hyperplasia is discouraged as hyperplasia by definition is a benign process) is a very common condition associated with advancing age being uncommon below 40 years of age but extremely common and increasing in frequency with age after age 50 years. It is seen at autopsy in over 95% of males, 70 years or older but the prevalence of clinically significant disease (symptomatic nodular hyperplasia) is much less, in the region of 5 to 10%. The condition is more common in blacks than in whites.

The cause of nodular hyperplasia is unknown. There is evidence that the disease is related to an imbalance of estrogen/testosterone/dihydrotestosterone created by advancing age. Prepubertal castration prevents subsequent development of nodular hyperplasia. In individuals with 5a -reductase deficiency, the enzyme that converts testosterone to dihydrotestosterone, the growth of the prostate is impaired. Administration of 5a -reductase inhibitors is associated with reduction in size of the gland in many cases of nodular hyperplasia. There is some experimental evidence in dogs that estrogens may also play a role in nodular hyperplasia. In aging men estradiol levels increase and may possibly be involved in the etiopathogenesis of this disease.

Symptoms of nodular hyperplasia are related to its secondary effects. The enlarged gland projects into the bladder impeding flow of urine by raising the internal urethral orifice, compressing and stretching and distorting the prostatic urethra. In some cases the enlargement involves mainly the median lobe, which forms a valve-like mechanism at the internal urethral orifice. As a result, the obstruction of the internal orifice increases as the patient strains. Patients present with frequency, nocturia, difficulty in initiating urination and stopping, overflow incontinence, dysuria and acute retention of urine. The enlargement involves mainly the central submucosal region of the gland. On cut surface, individual nodules are well defined each surrounded by a fibrous pseudocapsule. The main peripheral tissue is compressed to form a thin rim beneath the prostatic capsule. Focal areas of infarction may be seen in larger nodules.

Nodular hyperplasia.

Microscopically, there is proliferation of epithelial cells of the glands and ductules, smooth muscle cells and stromal fibroblasts in variable proportions producing nodules of differing compositions. Glandular hyperplasia takes the form of small to large to cystically dilated glands, arranged back-to-back and lined by an inner layer of tall columnar and an outer cuboidal or flattened cells. Numerous papillary projections and infoldings are present in the glands. Areas of infarction accompanied by foci of squamous metaplasia of duct epithelium may be present. Intraglandular and stromal chronic inflammatory cell infiltrates are common.

Low magnification view of nodular hyperplasia of the prostate showing crowded glands separated by stroma.

Medium power view showing back-to-back arrangement of glands with papillary intraglandular projections. Two corpora amylacea are present.

High power magnification. The two-layer epithelium is obvious and there is a lack of cellular pleomorphism. Nucleoli are indistinct unlike in PIN (see under neoplasm) where they are prominent.

Low power view of an area of stromal hyperplasia. No glands are present.

High power view of the same area showing bundles of smooth muscle.

Nodular hyperplasia is an entirely benign condition with no relationship to prostatic adenocarcinoma. Chronic retention of urine leads to distention and hypertrophy of the urinary bladder and urinary stasis and urinary tract infection. Prolonged, severe urinary obstruction causes backpressure, hydroureter, hydronephrosis and ultimately renal failure and death.

Objectives Anat & Hist Benign Neoplasms